PI, PLI, ER, HQ, HI, and CR index values of sediment samples during the summer were higher than those during the winter. This is attributed to the greater heavy metal concentrations and the lower water flow during summer. Our results provide practical information for better management and control of heavy metal pollution in aquatic-sedimentary ecosystems.The anthropogenic heavy metal dissemination in the natural environment through riverine sediments is a major ecological and public health concern around the world. This study gives insight into the source apportionment and potential ecological and health risks of heavy metals in river sediments of the Urmia Lake basin, a natural world heritage located in northwestern Iran. A comprehensive sediment sampling was conducted in seven major rivers feeding the basin during the summer and winter of 2021. Samples were analyzed for zinc (Zn), copper (Cu), cadmium (Cd), lead (Pb), and nickel (Ni) contents and a suite of chemical and physical properties. Subsequently, Pollution Index (PI), Pollution Load Index (PLI), Ecological Risk (ER), Hazard Quotients (HQ), Hazard Index (HI), and Carcinogenic Risk (CR) indices were determined. The mean concentration of heavy metals in all rivers’ sediments exhibited the descending order of Ni > Zn > Pb > Cu > Cd during both summer and winter. Multivariate analysis suggested that Zn was primarily initiated from natural processes, Cd and Pb were affected by human activities, and Cu along Ni were derived from natural and anthropogenic factors. The PI unveiled that most sediment samples were unpolluted to slightly polluted by Zn, Cu, and Pb, and slightly to moderately polluted by Cd. PLI and ER indices demonstrated that the sediment poses non to moderate pollution and low to moderate ecological risk, respectively. Using a human health risk approach, we found that the HI values of all heavy metals and THI were less than one for children and adults implying non-carcinogenic risk in the analyzed sediments. Carcinogenic effects of Cd and Pb at all rivers sediments via ingestion, inhalation, and dermal contact were almost within tolerable risks (1 × 10 Sediments are important sinks and carriers of heavy metals in the land–water transition zone, retaining almost 99% of the adsorbed metals after entry into the aquatic ecosystems4. Circulation of heavy metals in the environment occurs mainly through biogeochemical processes. However, human activities such as mining and manufacturing increase the diversity and concentration of heavy metals in terrestrial and aquatic ecosystems, thereby enhancing the potential of exposure and toxicity for different organisms5. Depending upon flow competence, particle size, and basin characteristics , flowing water has a substantial role in the dissemination of sediments-associated heavy metals across the water-soil–plant-human domain6. Benthic organisms in aquatic environments are more exposed to heavy metals through the bioturbation of sediments. This process re-distributes the heavy metals associated with the underlying sediment, thereby increasing the bioavailability and exposure potential for non-benthic organisms7. Migration of fish and transport of metals throughout species within the food chain exacerbates the distribution of sediment-associated heavy metals in aquatic ecosystems8. Heavy metals attracted by sediments may persist in the natural environment for long periods due to their specific physicochemical characteristics―e.g., high density, non-biodegradability, bioaccumulation, the long half-life, and difficulty to remove via self-purification10.The accumulation of heavy metals in sediments is a major threat to aquatic ecosystems and other components of the natural environment12. Some heavy metals can be dissolved and others may attach to the suspended particles after entering the aquatic environment from various sources, thereby settling in the sedimentary substrate with a progression over time13. Thus, sediment is a fundamental and dynamic part of the aquatic ecosystems―bearing physical and biogeochemical characteristics that determine the potential environmental risk. The assessment of these traits provides critical information about the significance of heavy metal pollution and guides environmental specialists toward specific remediation strategies14. Likewise, such information will assist governments, policymakers, and environmental activists to gain insight into the relationships between coastal development and its sustainable management to protect shorelines from worldwide heavy metal pollution15.Heavy metals are naturally initiated by lithogenic processes as well as anthropogenic activities 7. Oral ingestion, inhalation, and dermal exposure are three major heavy metals entry routes to the human body16. Specific metal transporters can move metals from apical to the basolateral surface to circulate throughout the organs by blood. Metals exhibit various oxidation states which facilitate their reactions in biological systems by losing electrons and generating reactive oxygen species (ROS) and free electrons17. Metals may be exerted through bile and urine, or they may accumulate in various tissues such as muscles, liver, and kidneys leading to various carcinogenic and other chronic disorders irrespective of age or gender18.Heavy metals-enriched sediments may be potential threats to the food chain and human health through different pathways2 is the second largest salt lake in the world19. This endorheic saltwater lake presents one of the rarest and most diverse biosphere reserves in Iran and the world20. The lake has been recognized by UNESCO as an environmental heritage and international wetland20. Over the past few decades, climate changes have substantially declined the net water discharge into the basin. On the other hand, the rapid growth of industrial units, expansion of residential and agricultural lands, and unsustainable natural resource management strategies have increased the load of heavy metals along with the other contaminants into Urmia Lake through runoff, and sediment transport. It has raised concerns regarding the contamination of shallow aquifers in the basin which are primary freshwater resources for humans, animals, and agricultural water use in the basin. Metals may form a range of more toxic compounds by interacting with nitrates, sulfates, carbonates, and other anions which are found in abundance in agricultural discharge21. Metals speciation can considerably enhance the bioavailability and bioaccumulation of metallic compounds in organisms, thereby threatening the highly diverse fauna and flora in the region. However, little information is available regarding the heavy metal pollution and associated health risk in the Urmia Lake basin. Improved understanding of the level of heavy metal pollution in sediments provides a critical decision support tool for stakeholders, including both government and the public communities to take proper actions to protect the unique ecological and wildlife ecosystem of the Urmia Lake basin. Therefore, the objectives of this study were to 1) investigate the level, distribution, and accumulation of heavy metals including Zn, Cu, Cd, Pb, and Ni in the river sediments of the Urmia Lake basin during two seasons, 2) assess the contamination rate and human health risks of heavy metals in the sediments of the study region using various evaluation techniques, and 3) explore the potential sources of heavy metals through multivariate statistical analysis.Urmia Lake, with a surface area of approximately 5200 km22 with a 30-year mean annual rainfall of approximately 364 mm. Varying based on the seasonal water recharge, Urmia Lake extends 140 km towards north–south directions and 16 to 63 km in east–west direction. Urmia Lake is a part of the Azerbaijan plateau as well as the northwestern part of the Iranian plateau which are dominated by a diversity of alluvial salts derived from Cretaceous , basic igneous rocks, and Quaternary rocks23. Following cut off Tethys seaway from the ocean in the Late Cretaceous, the shallow intermountain lakes and lagoons are formed in the Tertiary in the Iranian plateau. Therefore, Urmia Lake likely is the remnants of the post-Tetyan sea and is rich in various salts and sediments.The study region is located in the northwest of Iran (36° 23′ to 38° 15′ N and 44° 32′ to 46° 15′ E) .Sediment sampling locations were selected as near headwater to discharge points of lower estuary of each river/stream flowing into the Urmia Lake during winter in January–February, 2021 and during summer in August and September 2021. Using the standard procedure3 with a ratio of 12:4 at 130° C for 5 h. Finally, 4 mL of concentrated HCIO4 was added to the solution. The sediment was filtered and washed using 0.1 M HNO3 solution and diluted to 50 mL with deionized water. Using a flame atomic absorption spectrophotometry , the zinc (Zn), copper (Cu), cadmium (Cd), lead (Pb), and nickel (Ni) concentrations were determined. The precision was inspected using reagent blanks, replicates, determination of limits of detection (LOD), and the parallel analysis of international reference materials26. To calculate the LOD, three times the standard deviations of the concentration of the relevant metal was considered over six spiked samples12. The LODs were 2, 1, 0.01, 1, and 1 mg kg−1 for Zn, Cu, Cd, Pb, and Ni, respectively. Moreover, the standard solution concentrations were 0.5, 1, 1.5, 2, and 2.5 or 4, 6, 8, 10, and 12 mg l−1 for Zn and Cu; and 0.5, 1,1.5, 2 and 2.5 mg l−1 for Cd, Pb, and Ni.Sediment samples were air-dried at 20–25 °C in ambient laboratory conditions, passed through a 2-mm sieve and stored for further laboratory analyses. All samples were analyzed to determine the main characteristics of sediments and the heavy metals concentration Table . Heavy m34. For each sediment sample, 15 g of sediment material was weighed, dried at 60 °C for 24 h, and then three drops of Triethanolamine (C6H15NO3) were added. After grinding the samples, 8 g of each was made into pellets and major element oxides were generated. The geochemical weathering indices were calculated using the following Eq. 35.Using an X-ray fluorescence (XRF) spectrometry , elemental analyses of sediment samples were estimatedCIA is the geochemical index of alteration and Al2O3, CaO, K2O, and Na2O are input moles of oxide molecules. CIA has been widely used to indicate the intensity of silicate weathering in the sedimentary basins36 .Here Three pollution indices were used to determine the degree of metal contamination in sediments of the Urmia Lake basin and to determine whether metal toxicity and the potential health risks endanger the life quality and the ecosystem of this region.Cm is the heavy metal content of sediment (mg kg−1), Cb is the reference concentration of sediment metals (mg kg−1), n is the number of metals, and PI and PLI are Pollution Index and Pollution Load Index. In this study, the geochemical background was estimated using the Median Absolute Deviation (MAD) method38, accounting for the mean earth crust values39. The pollution index was categorized into unpolluted (PI ≤ 1), slightly polluted (1 < PI ≤ 2), moderately polluted (2 < PI ≤ 3), and highly polluted (PI > 3) levels37. Moreover, the PLI value was classified as no pollution (PLI < 1), moderate pollution (1 < PLI < 2), high pollution (2 < PLI < 3), and extremely high pollution (PLI > 3)37. Pollution and pollution load indices are effective tools to evaluate the magnitude of contaminants in the environment and are commonly used to appraise the status of heavy metals in various ecosystems37.40.ER is the total ecological risk factor of the metals, −1 for Cu, Pb, and Ni, 30 mg kg−1 for Cd, and 1 mg kg−1 for Zn. 41. The ER, ecological risk factor was explored within four intensity classes; low risk (ER < 150), moderate risk (150 ≤ ER < 300), considerable risk (300 ≤ ER < 600), and high risk (ER > 600)40.The ecological risk of heavy metals pollution for aquatic organisms was assessed based on the productivity response of aquatic ecosystem to the potential heavy metal pollution42:The potential non-carcinogenic and carcinogenic health risks of heavy metals to children and adults via ingestion, inhalation, dermal contact was assessed separately using the following Eqs. ADDing, ADDinh, and ADDderm are the Average Daily Dose (ADD) uptake from sediment ingestion, inhalation, and dermal contact, respectively (mg element per kg−1 bodyweight day−1) and C is the heavy metal concentration in a given sediment sample (mg kg−1). Other parameters including IRing, AT, BW, IRinh, ED, EF, PEF, ABS, AF and SA are presented in Table S143.Here 42.Non-carcinogenic risk of heavy metals was calculated using the hazard quotient (HQ), represented by the quotient of the ADD of each heavy metal and the corresponding reference dose Eqs. –1118,25,Here, HI and THI are hazard index and total hazard index, respectively. HI/THI > 1 represents a significant non-carcinogenic effect to the public, whereas HI/THI < 1 indicates no apparent non-cancer risk to the public.44:Similarly, carcinogenic risk was calculated using Eqs.  and 1344CR is the carcinogenic risk from each metal, SF is the slope factor (kg day mg−1), and TCR is the total carcinogenic risk indexes. The carcinogenic risk of heavy metals was categorized into negligible (CR/TCR < 1 × 10−6), admissible risk (1 × 10−6 < CR/TCR < 1 × 10−4), and impermissible risk (CR/TCR > 1 × 10−4) classes44.Here, 50) of heavy metals extracted from the sediment material. The TU of chemicals in the mixture was calculated using the following Eqs. 45.i is the toxic unit of ith heavy metal in the mixture, Ci is the concentration of ith heavy metal in the mixture at IC50 which is the median inhibition concentration.The Toxicity Unit (TU) was obtained by determining the half maximal inhibitory concentration (IC46 using GLM procedure. Least squared means were separated using Fisher’s least significant difference (LSD) test at 95% confidence interval. The normality of data distribution was satisfied according to Shapiro–Wilk > 0.9, otherwise log-transformation was performed. Principal component analysis (PCA) was performed to reduce the multicollinearity among variables and to identify the possible type of heavy metal pollution in the rivers.All descriptive statistics  were conducted by Microsoft Excel 2016. The Analysis of Variance (ANOVA) was conducted in SAS (version 9.4)−1), silt (145 to 656 g kg−1), and sand (38 to 821 g kg−1) particles among sediment materials. The associated coefficient of variations (CV) was 57, 59.5, and 41%, respectively. Statistical data related to the physicochemical properties of sediments and their main elements are reported in Table −1, respectively, indicating the dominancy of alkaline-calcareous condition. None of the sediment samples exhibited salinity conditions (EC > 4 dS m−1) with EC in the range of 0.3 to 1.4 dS m−1. A relatively low range of OM was found in all samples ranging from 7 to 61 g kg−1 with a mean value of 19 g kg−1. This range of OM coincides with the corresponding values in regional soils47. Except for pH, other sediments properties demonstrated above 35% of CV illustrating a wide range of variability in sediments’ physicochemical properties across the study rivers.A considerable variation was found in the distribution of clay , CaO (5–14.3%), Fe2O3 (4.8–10%), MgO (2.4–17.2%), K2O (1.2–3.1%), Na2O (0.68–2.7%), SO3 (0.01–4.8% g kg−1)  in the region36.The highest concentration among major elements was observed in SiO50. The positive relationship between heavy metals concentration in sediments and the river flow depth and rate has been thoroughly observed in previous studies52. The mean annual concentrations of heavy metals except Pb, varied significantly across studied rivers  and Fe2O3 (r = 0.4 to 0.7) content, illustrating that Al and Fe oxides considerably increase the heavy metal retention capacity of sediments. These correlations are consistent with previous observations56, which highlighted the substantial increase of heavy metals absorbance in presence of aluminum and iron oxides in mineral particles. Significant positive correlations were found between Cd and Pb (p < 0.01) concentrations in given riverine sediment material whereas less significant correlation coefficient found between Ni and Cu, implying an analogy in transport-accumulation mechanism and sources of these metal pairs57. Similar observations are reported by Ustaoğlu and Islam58 in sediments of a few rivers in Giresun, northeast Turkey, and Shu et al.4 in the surface sediments of tidal flats along the north Jiangsu coast, China. The lack of significant correlation between Zn on one hand and Cu, Cd, Pb, and Ni on the other hand corroborate that this element may not have a common sources and transport mechanism with other metals.The Pearson's correlation analysis was conducted to identify the sediment properties that may exert a control on sediment’s heavy metal adsorption capacity Fig. . The maj59. The ANOVA revealed significant differences in PI values among the rivers  was calculated to assess the impact of sediment pollutants on the aquatic organismsder (a range of 2.18E−08) and HQinh (a range of 4.35E−05–0.167). This result implies that the non-carcinogenic risk of diseases caused by the ingestion of all heavy metals from the riverine sediment of the region is much more hazardous than that by dermal contact and inhalation. These observations are analogous to the findings of the studies conducted by Proshad et al.52 and Şimşek et al.2. The HQ ranking of metals demonstrated the descending order of Pb > Ni > Cd > Cu > Zn for three exposure pathways and both age groups and seasons. In accordance with the previous studies58, the observed trend indicates a greater role of Pb in the incidence of non-carcinogenic risk than the other metals.The health risk of Zn, Cu, Cd, Pb, Cd to induce non-carcinogenic diseases via ingestion, inhalation, and dermal contact was calculated for children and adults separately Table . The HQ 67. Heavy metals can cause various health issues in children e.g., skeletal injuries, cardiovascular disease, or respiratory system and productivity68. For both summer and winter sediments, the mean values of THI across the seven rivers followed a descending order as BAR > NAZ > GAD > SHA > MAH > SIM > ZOL and BAR > NAZ > GAD > MAH > SIM > SHA > ZOL for children and adult, respectively , inhalation (CRinh), and dermal contact (CRder) of sediments . During summer, the TCR (∑CR) values for Cd and Pb in children and adults ranged from 1.4E−05 to 1.53E−04 and 1.26E−06 to 1.36E−06 for Cd and from 2.64E−06 to 1.24E−05 and 2.33E−07 to 1.1E−06 for Pb, respectively. Regarding the winter, the corresponding ranges of TCR-Cd were 1.26E−05 to 1.43E−04 for children and 1.21E−06 to 1.27E−05 for adult while TCR-Pb ranged from 2.43E−06 to 1.16E−05 for children and 2.18E−07 to 1.05E−06 for adult. These results suggest that both children and adult were almost within tolerable risks (1 × 10−6 to 1 × 10−4) of carcinogenic hazards to human health. The mean value of TCR (Cd + Pb) was in rang of 4.56E−05 over winter to 5.03E−05 in summer and 4.05E−06 to 4.46E−06 for children and adult, respectively. The comparison of these data implies that the risk of TCR (Cd + Pb)-initiated cancer in children  was 11.2 to 11.3 times higher than in adult . This distinction may also be explained by children’s behavioral patterns which encourages the propensity for their skin particularly hand-to-mouth activities67.The carcinogenic risk potential (CR) of Cd and Pb was calculated for children and adult through ingestion   Fig. , which w−6 < CR < 1 × 10−4), signifying no non-carcinogenic and carcinogenic risk of the metals in the study region. The value of PI, PLI, ER, HQ, HI, and CR of sediments were higher in summer than those in winter, implying that the study sediments were under a higher intensity of heavy metals loads during summer. This study brings insight into the source, dissemination potential, and human health risk of heavy metals introduced from various resources to the river ecosystems in Urmia Lake basin. This information is expected to raise awareness about the facilitated introduction of heavy metals to the food chain through intensified dissemination through river flow. Continuous monitoring of heavy metals in water–sediment-aquatic biota system in Urmia Lake basin is essential for safeguarding the human, animal, and environmental health.We studied the distribution, source apportionment, contamination statuses, ecological impacts, and human health risk of Zn, Cu, Cd, Pb, and Ni in river sediments of the Urmia Lake basin, NW of Iran. The mean concentration of five heavy metals analyzed in the sediments of 7 rivers and during summer and winter was as follows: Ni > Zn > Pb > Cu > Cd with different spatial and temporal distributions along the rivers. Multivariate statistical methods show that the study sediments are under the influence of anthropogenic origin particularly by Cd and Pb. Approximately 73.5% of the summer sediment and 79.4% of the winter sediment showed “no pollution” (PLI < 1). Based on the ER index, 97.1% of both summer and winter sediments were ranked below “low ecological risk” and Cd is the primary heavy metal accountable for ecological threats followed by Pb, Ni, Cu, and Zn. The HI and CR for exposure of both children and adults to heavy metals fell within the accepted standard levels (HI < 1, 1 × 10Supplementary Information.


Our aim was to compare cerebrovascular and systemic vascular function between older adults with and without mild cognitive impairment (MCI), and to determine which measures of vascular function best predict the presence of MCI.2, and responsiveness to changes in blood pressure (%∆MCAv/%∆MAP). Systemic vascular function was assessed by flow-mediated dilation (FMD) and stiffness by pulse wave velocity (PWV).In 41 adults with MCI and 33 adults without MCI (control) we compared middle cerebral artery velocity (MCAv) and cerebrovascular pulsatility index (PI) at rest, cerebrovascular reactivity to COp = 0.76) and relative cerebrovascular reactivity to CO2 (p = 0.34) was similar between MCI and control. When age was included as a covariate the significant difference in cerebral PI between groups was lost. PWV was higher (13.2 ± 2.2 vs. 11.3 ± 2.5 m s−1) and FMD% (4.41 ± 1.70 vs. 5.43 ± 2.15%) was lower in MCI compared with control. FMD% was positively associated with PI across the cohort. Logistic regression analysis indicated that FMD and PWV significantly discriminated between MCI and controls, independent of age, whereas the inclusion of cerebrovascular measures did not improve the predictive accuracy of the model.Cerebrovascular PI was higher in MCI compared with control (mean ± SD: 1.17 ± 0.27 vs. 1.04 ± 0.21), and MCI exhibited a lower %∆MCAv/%∆MAP (1.26 ± 0.44 vs. 1.50 ± 0.55%). Absolute (These findings raise the possibility that early changes in systemic vascular stiffness and endothelial function may contribute to altered cerebrovascular haemodynamics and impaired cognitive function, and present potential targets for prevention and treatment strategies in people with MCI.The online version contains supplementary material available at 10.1007/s00421-022-04956-w. The prevalence of dementia is increasing and is expected to directly affect 74 million adults worldwide by 2030 WHO . Prevent2 and perturbations in blood pressure, i.e. dynamic autoregulation, are conflicting  ultrasonography to investigate the intracranial arteries, there is evidence that the velocity of cerebral blood flow (CBFv) is lower, indicative of chronic hypoperfusion, in adults with MCI , and elevated pulse wave velocity (PWV), are associated with poor cognitive performance and steeper declines in cognition with age  and control participants (n = 33). Those with MCI were recruited through the NeuroExercise project  and was approved by the institutional human research ethics committees. Participants provided written informed consent and were screened to ensure they met the inclusion criteria prior to participation.This study included a comparison of adults with MCI , and heart rate (HR) which were recorded throughout the study session. After resting supine measurements were obtained, cerebrovascular CO2 reactivity was assessed using a breath-hold test. Participants then performed a repeated stand-to-sit test for the determination of cerebral pressure-flow responsiveness. Baroreflex sensitivity was also assessed during the repeated stand-to-sit procedure. Following this, participants underwent a further 15 min of supine rest prior to assessments of peripheral and central blood pressure, wave reflection characteristics, and carotid-femoral PWV. Finally, participants underwent a test of brachial artery FMD as a measure of systemic endothelial function. All assessments were conducted in a quiet, temperature controlled (23 ± 0.5 °C) laboratory.After screening, all participants attended the laboratory on a single occasion to undergo a series of cerebrovascular and systemic vascular assessments. Participants refrained from alcohol and exercise for 24 h and caffeine for 12 h before the session and continued to take prescribed medication. Participants were fitted with instruments to measure middle cerebral artery blood flow velocity (MCAv), mean arterial blood pressure (MAP), end-tidal carbon dioxide (PVs − Vd)/Vmean]  was calculated using Gosling and King’s equation [PI =  was calculated by subtracting the average over the last two breaths before the breath-hold from the peak PETCO2 response immediately after the breath-hold. The first two breath-hold manoeuvres were used to familiarise participants with the procedure (Tancredi and Hoge ETCO2 as absolute (∆MCAv/∆PETCO2) and relative (%∆MCAv/∆PETCO2) responses.Cerebrovascular reactivity was assessed as the MCAv response to changes in PETCO2. Whereas for HR responses, maximum values were identified during the stand phase and minimum values during each sit phase. For each transition, the response of each variable was calculated using the delta (sit − stand). The transition delta responses were also expressed as a percentage of the stand phase values (%∆), and the ratio of %∆MCAv/%∆MAP was calculated for each transition as previously reported . This same protocol has previously been used in older adults . Heart rate was monitored by ECG and blood pressure was measured continuously at the left middle- or index-finger using photoplethysmography . Participants breathed through a leak-free respiratory mask , and expired air was continuously sampled for the determination of PETCO2. All variables were sampled at 1000 Hz and stored . Time-aligned signals were then resampled to second-by-second (1 Hz) for visual inspection and analysis.MCAv was measured continuously using transcranial Doppler ultrasonography (TCD) where a 2 Hz probe was placed over the right temporal window and fixed at a constant angle with a customised headband . The MCAv signal was identified according to standardized criteria guided by signal depth, velocity and wave characteristics  and backward (Pb) pressure waveforms, which were expressed as the wave reflection magnitude . This method assumes a triangular-shaped flow wave approximated from the estimated aortic pressure wave  between the carotid and femoral sites multiplied by 0.8, divided by the time delay (s) between the pulse waves . These tests have previously been described in detail . Our laboratory has previously reported a between and within day coefficient of variation (CV) for FMD% of < 10%  and cerebral (%MCA/%MAP and PI) measures of interest were able to discriminate between MCI and control. Age was entered at Step 1, followed by the systemic and cerebral variables of interest at Step 2. Large confidence intervals were observed for the odds ratio for PI. To address this, PI scores were subsequently categorised as high versus low . However, treating PI as a categorical variable did not affect the results and thus raw values are reported.Based on the mean effect extracted from a pooled dataset of > 500 MCI and control participants across multiple studies .Pearson’s correlation coefficients were used to examine the relationships between cerebrovascular and systemic function responses in the MCI and control groups. The effect size is reported as low if the value of r is around 0.1, medium if .5 Cohen . Statistn = 41, CON: n = 33) was available for the analysis of MoCA scores and other participant characteristics, as well as the assessment of central blood pressure and augmentation index. Due to technical difficulties in obtaining reliable MCAv or finger blood pressure signals during the sit-to-stand test, there were seven missing cases from the MCI group ; and an additional four missing MCI cases for the cerebrovascular reactivity dataset because of difficulties performing the breath hold manoeuvre . For the assessment of pulse wave velocity there were four missing cases from the MCI group and three missing cases from the CON group  because a reliable 10 s carotid artery pulse wave signal could not be obtained. Flow mediated dilation could not be assessed in two MCI cases due to poor ultrasound image quality . Analyses were carried out with all available data without substitution or imputation for missing cases.A complete dataset (MCI: p = 0.001); and the MCI group also had a significantly lower MoCA score (p < 0.001). The significant difference in MoCA scores between groups remained when accounting for age (p < 0.001). Resting heart rate, peripheral blood pressures, and BMI were all similar between groups. There was a difference in aspirin medication use between MCI and controls (p < 0.001), and higher beta blocker use in MCI (p = 0.06); but the use of other medications was similar between groups.Participant characteristics are presented in Table p = 0.03), but this effect was lost when accounting for age as a covariate (p = 0.35). Cerebral pressure-flow responsiveness and cerebrovascular reactivity to CO2 are presented in Tables ETCO2 and MAP were not different between MCI and control groups. The MCI group showed a lower %∆MCAv/%∆MAP response than the control group (p = 0.048). When accounting for age the difference in the %∆MCAv/%∆MAP was lost (p = 0.08).Cerebrovascular outcomes are presented in Table ETCO2 was similar between groups during the breath-hold test. While the change in MCAv was significantly higher in control compared to MCI (p = 0.014), the peak MCAv also tended to be higher in control compared to MCI, but this did not reach statistical significance (p = 0.064). The cerebrovascular conductance (CVC) reactivity to CO2 (p = 0.761) and relative cerebrovascular reactivity (p = 0.341) was similar between MCI and control groups. Findings for cerebrovascular reactivity were unaffected when accounting for age as a covariate (p = 0.75).The change in Pp = 0.002). Brachial artery FMD% was lower in MCI compared to control (p = 0.030). When accounting for age as a covariate, the significant differences in both PWV (p = 0.004) and FMD% (p = 0.02) remained. Across both cerebrovascular and systemic vascular outcomes, we observed similar differences between MCI and control groups when the male and female cohorts were considered separately (Refer to Online Resource: Supplementary Table 1). While some of the group differences were no longer statistically significant, the magnitude of the differences in means were similar to the effects reported in the full cohort.Indices of central blood pressure, wave reflection characteristics, pulse wave velocity and vascular function are presented in Table χ2(1) = 8.601, p = 0.003, Nagelkerke R2 = 0.178 (Table χ2(4) = 17.98, p = 0.001, Nagelkerke R2 = 0.477). However, only the systemic measures contributed significantly to the model. Accordingly, a second logistic regression analysis was performed, excluding the cerebral measures.Age significantly predicted group membership, accounting for 17.8% of the variance (78 Table . Adding Including systemic vascular outcomes only (FMD and PWV) accounted for 72.3% of the sample variance Table . For eacn = 71, r = 0.28, p = 0.017). Cerebrovascular PI was associated with systolic blood pressure in the pooled cohort , and this association was stronger in MCI  than in control . Cerebrovascular PI was also negatively associated with diastolic MCAv at rest when examining the pooled cohort . These findings are shown as an Online Resource . When considered separately, this association remained significant in control  and in MCI . We found no significant associations between PWV and cerebrovascular parameters in MCI or control groups (p > 0.05). FMD% was positively associated with PI in the pooled cohort , and this association was strong in MCI , but not in control .Correlations between MoCA scores and the cerebral and systemic outcomes are presented as an Online Resource (Supplementary Table 2). MoCA score was associated with FMD in the pooled cohort . We observed a higher cerebral PI and lower cerebrovascular responsiveness to changes in blood pressure (stand–sit test) in adults with MCI compared with control participants. For systemic vascular outcomes we observed higher aortic stiffness (PWV) and lower systemic endothelial function (FMD) in adults with MCI compared to control. When controlling for age, the observed differences in cerebral outcomes were lost and only systemic vascular outcomes (FMD and PWV) differed between MCI and control. This suggests that MCI is likely responsible for the differences we observed in systemic vascular outcomes.Resting cerebral blood velocity (MCAv) was similar between groups in this study. Previous studies have shown that cerebral blood flow gradually decreases across the spectrum of cognitive impairment, particularly when investigations include adults across a wide spectrum of disease severity . This is in line with the findings of De Heus et al.  and endothelial dysfunction (FMD) predicted the presence of MCI in this study, independent of age. In contrast, cerebrovascular outcomes did not distinguish between MCI and healthy adults. Interestingly, when we accounted for age differences between the MCI and control groups, any differences in cerebrovascular function were lost. This is in line with previous findings showing no significant differences in cerebrovascular outcomes in healthy adults who are elderly (65 + years) and older-elderly (74 + years) Below is the link to the electronic supplementary material.


This study aimed to investigate sexual orientation disclosure and mental health among young men who have sex with men (YMSMs). To this end, we constructed a chained multimediator model of sexual minority stigma, sexual minority identity, social support, and resilience, with the moderator of sexual orientation disclosure.We conducted a cross-sectional survey of 345 YMSMs in Nanning, China. Bivariate analysis was used to evaluate factors associated with sexual orientation disclosure. Sexual minority stigma was used to predict identity, with social support as the step 1 mediator and resilience as the step 2 mediator. Sexual minority identity was analyzed using a chained moderated mediation model; sexual orientation disclosure was included as a moderator in all models to control its confounding effect.p < 0.05). Sexual minority stigma, perceived stigma, and enacted stigma were significantly associated with social support and resilience. The association between sexual minority stigma and sexual minority identity was significantly mediated by social support . Resilience significantly mediated the same association for identity . The chained relationship from sexual minority stigma to social support, resilience, and identity was also significant, with an indirect effect of − 0.404 .The average age of YMSMs was 20.0 ± 1.3 years. Bivariate analysis indicated that YMSMs who disclosed sexual orientation may have experienced less stigma (15.49 ± 3.02 vs 16.21 ± 2.74), obtained more social support (65.98 ± 11.18 vs 63.19 ± 11.13), had strong psychological resilience (37.40 ± 8.57 vs 35.39 ± 7.73), and had a more positive self-identity (104.12 ± 21.10 vs 95.35 ± 16.67); differences between subgroups were statistically significant (Among YMSMs in China, sexual minority stigma affects sexual minority identity through social support and resilience. Given the psychological effects of stigma, social support and resilience must be considered to better promote positive self-identity and mental health among YMSMs. It has been estimated that 83.0% of the global sexual minority population conceals its sexual orientation from all or most people . Such coSexual minority stigma refers to the social and structural devaluation of lesbian, gay, bisexual, and other sexually diverse people and the associated power inequalities, negative attitudes, and stereotypes . A . A 49]. Sexual minority stigma was evaluated using Neilands’s questionnaire, Assessment of Stigma Toward Homosexuality in China . This scSocial support was measured using the Multidimensional Perceived Social Support Scale . It inclA modified Connor–Davidson Resilience Scale  was usedSexual orientation disclosure was defined as having ever disclosed one’s sexual orientation to anyone other than a sexual partner. Healthcare professional disclosure means disclosing to a doctor or other medical provider. Studies have indicated that the association between sexual minority stigma and sexual minority identity differs by orientation disclosure [sclosure , 53. To Sexual minority identity was measured using the Lesbian, Gay, & Bisexual Identity Scale . It is d3’ provided a measure of the moderating effect of orientation disclosure. In step 3, chained mediation modeling with two mediators was conducted. As shown in Fig. 1 and b1 (a1*b1), a2 and b2 (a2*b2), and a1, a3, and b2 (a1*a3*b2) provided measures of the indirect effects of sexual minority stigma → social support → sexual minority identity, sexual minority stigma → resilience → sexual minority identity and sexual minority stigma → social support → resilience → sexual minority identity, respectively.Descriptive analyses were used to describe the study sample and for bivariate analysis by the sexual orientation disclosure subgroup. We tested the proposed chained mediation model in three steps. In step 1, Pearson’s correlation was used to investigate correlations among the key variables, including sexual minority stigma, social support, resilience, and sexual minority identity. In step 2, moderated mediation modeling was used to test the individual roles of social support and resilience in mediating the association between sexual minority stigma and sexual minority identity , considering the moderating role of orientation disclosure. As shown in Fig. p < 0.05 for statistical inference. Moderated mediation analyses were conducted using Mplus 8.3.Two investigators used Epidata 3.1 to enter the questionnaire data, save the final database after consistency checks, and import it into SPSS 24.0 for descriptive analysis. Type I error was set at A total of 61.7% of participants were Han, and one-third were Zhuang; 79.1% had a college education or higher; 50.1% were staff; 56.2% made 3000 RMB or more; 67.8% reported their sexual orientation as gay. The chi-squared test showed significant statistical differences in sexual orientation disclosure between the self-reported sexual orientation groups (Table t-test, there were statistical differences in the scores for sexual minority stigma, social support, resilience, and sexual minority identity between subgroup according to whether sexual orientation was disclosed. YMSMs who disclose sexual orientation might experience less stigma, obtain more social support, have strong psychological resilience, and have a positive self-identity. However, different from perceived stigma, enacted stigma showed no significant statistical difference between subgroups (Table In the bivariate analysis ps Table . For sexSexual minority stigma, perceived stigma, and enacted stigma were significantly associated with social support and resilience. Social support was significantly associated with resilience; both were significantly associated with sexual minority identity. This supports the proposed mediation models. Additionally, Table We analyzed data of moderated mediation modeling in Fig. The results shown in Fig. As the concept opens up, we can find the number of YMSMs disclosure sexual orientation has increased, about half of YMSM have told others about self-sexual orientation. Our results revealed a significant relationship between mental health and sexual orientation disclosure among Chinese YMSMs. YMSMs who were “coming out” were more likely to have good mental health, as in previous studies . So, we Perceived stigma refers to expectations of stigma and prejudice, which cause stress by requiring vigilance. It is assessed as a person’s level of awareness of being stigmatized and devalued by their community [Enacted stigma refers to experiences of victimization, harassment, threats, and discrimination in daily life, at work, and in housing situations [One important finding is the demonstration of the effect mechanism of stigma on sexual minority identity, mediated by social support and resilience. Social support and resilience are two important factors related to self-identity , 56. Higommunity . Enactedtuations . For theOur findings also revealed a chained mediation mechanism in which the relationship between sexual minority stigma and identity was mediated by both social support and resilience. Other studies have also observed indirect effects through the associated mediators of social support and resilience , 63, 64.A positive sexual minority identity among YMSMs can reduce the effects of perceived stigma; it has chain mediating effects in the two key target variables of social support and resilience. Compared to total stigma, the effects of perceived stigma and enacted stigma were not significant; this warrants additional research in the future.This study has some limitations. First, it was a cross-sectional study limited to one city in China; caution should be exercised with regard to generalizing the findings. Future studies can use a prospective longitudinal research design and collect data in more cities. Second, the variables were self-reported, and underreporting cannot be ruled out resulting from social desirability bias, Future studies may overcome this limitation through communicating more with the participants and taking feasible and effective measures to gain more trust to strengthen the authenticity of the data. Third, we only considered the comparison of discrimination perception between YMSMs who were in or had been in a marriage and who were not. possibly in future studies, the content of the questionnaire can be improved to create additional category like "Being in a relationship but not marred”.Our findings highlight the importance of considering social support and resilience in the effect of sexual minority stigma on mental health among YMSMs. Reducing stigma and giving more social support are effective measures for intervening in the mental health of YMSMs. The chain mediating effect results showed that sexual minority stigma, sexual minority identity, social support, and resilience regulate and influence each other and provide a basis for YMSMs’ mental health regulation. Combined with longitudinal data, this study’s findings could be used to inform interventions targeting mental health and HIV prevention among YMSMs in China.


This study aimed to investigate the effects of gallic acid and silymarin against nephrotoxicity and hepatotoxicity caused by cisplatin.  In the study, 56 Wistar Albino rats were equally divided into eight groups. Group 1 was the control group; group 2 was the group receiving cisplatin; group 3 was the group receiving cisplatin + gallic acid; group 4 was the group receiving cisplatin + silymarin; group 5 was the group receiving cisplatin + silymarin + gallic acid; group 6 was the group receiving silymarin; group 7 was the group receiving gallic acid; group 8 was the group receiving gallic acid + silymarin. AST, ALT, urea, creatinine, albumin, globulin, and total protein levels were measured at the end of the study. Superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), glutathione (GSH), and 8-hydroxy-2′-deoxyguanosine (8OH-dG) levels were measured in kidney and liver tissues. Additionally, histopathological evaluations of the tissues were also performed. p < 0.05). Silymarin-treated group significantly increased the SOD activity and GSH amount in the liver tissue compared with the cisplatin-treated group (p < 0.05). Gallic acid significantly increased CAT activity compared with the cisplatin-treated group (p < 0.05). It was determined that the cisplatin-treated group significantly decreased CAT and SOD activity compared with the control group (p > 0.05). Gallic acid showed a significant increase in CAT and SOD activity in kidney tissue compared with the cisplatin-treated group (p < 0.05).  In kidney and liver tissues, cisplatin significantly increased MDA and 8-OHdG levels compared with treatment groups ( As a result, it was observed that gallic acid silymarin had a protective effect on cisplatin-induced nephrotoxic and hepatotoxic effects. The formation of factors such as air pollution, nutritional disorders, tobacco, and alcohol consumption in recent years has led to an increase in free radicals in the body and the emergence of many diseases such as cancer . Cells aIt is known that plants and fruits contain antioxidant components that contribute to body defense against oxidative stress , 4. In lSilymarin, which is used as a strong antioxidant thanks to the phenolic structures it contains, draws attention with its protective feature against toxic effects. Silymarin is called a hepatoprotectant with a short half-life and rapid conjugation in the liver . In a stGallic acid, which is a phenolic acid found in many foods and herbs, shows itself as a powerful antioxidant. It has been determined that gallic acid has antioxidant properties by scavenging free radicals directly . In the The drugs used have many side effects. Therefore, many studies have been carried out to minimize or eliminate these side effects. Although cisplatin is a widely used chemotherapeutic agent, its use has been limited due to its side effects . PossiblThe fact that both silymarin and gallic acid are strong antioxidants and have protective effects in line with the studies led us to investigate their effects against cisplatin-induced nephrotoxicity and hepatotoxicity. Since there is no previous study with these two components, our research is an original study.In the study, 56 male Wistar albino rats, 8–10 weeks old, weighing 150–250 gr, obtained from Van Yüzüncü Yıl University Experimental Medicine Application and Research Center were used. During the experiment, the rats were housed in cages with 12 hours of darkness/lighting in rooms with a temperature of 22 ± 2°C, with constant feed and fresh water in front of them. The Animal Experiments Local Ethics Committee of Yüzüncü Yıl University approved the study .In the study, 56 male Wistar albino rats were randomly selected, with seven rats in each group, and eight groups including the control group were formed as follows: group 1 was the control group; group 2 was the group receiving cisplatin; group 3 was the group receiving cisplatin + gallic acid; group 4 was the group receiving cisplatin + silymarin; group 5 was the group receiving cisplatin + silymarin + gallic acid; group 6 was the group receiving silymarin; group 7 was the group receiving gallic acid; group 8 was the group receiving gallic acid + silymarin.During the seven-day study, 8 mg gallic acid and silymarin per kg were dissolved in water and administered via gastric gavage . On the After the seven-day experiment, ketamine (75 mg/kg) and xylazine (10 mg/kg) were administered ip to the rats that were fasted for 12 hours. Intracardiac blood samples were taken into vacuum tubes with and without anticoagulants.After the blood samples were taken, the kidneys and livers of the rats, which were sacrificed by the bloodless method, were removed. It was stored at −80°C until analysis.μm thickness, taken with a microtome from kidney and liver tissues embedded in paraffin blocks, were stained with hematoxylin-eosin dye and examined under a light microscope . Photographing was done with the Olympus DP74 microscope camera and Olympus cellSens software. For histopathological evaluation, a mean of 15 fields for each animal in the groups was evaluated by random sampling. The findings were evaluated semiquantitatively according to the degree of damage observed in the examined regions. Accordingly, scores were as follows: normal tissue: −; minor damage: + (damage <25%); minor damage: ++ (25–50%); medium damage: +++ (50–75%); severe damage: +++ (damage >75%).After the rats were anesthetized with ketamine and xylazine, the kidneys and liver tissues were removed. The excised tissues were fixed in buffered formaldehyde. Then, after going through routine histological tissue follow-up stages, it was embedded in paraffin. Sections of 5 Phosphate buffer (pH: 7.2–7.4) was added to the kidney and liver tissues at 10 times their weight. It was homogenized with the aid of a homogenizer. Care was taken to ensure the cold chain at all stages of the experiment. The homogenates were centrifuged at 2000–3000 rpm, +4°C for 20 minutes . GSH levp < 0.05 was considered statistically significant.SPSS v.20  package program was used for statistical analysis. All data were expressed as mean ± standard deviation. Statistical analysis of the groups was performed using the one-way ANOVA followed by post hoc multiple comparisons (Tukey's test) for comparative analysis between the groups. p < 0.05). It was determined that the level of 8-OHdG decreased significantly in the cis + gal group compared with the cisplatin group (p < 0.05).Serum GSH, CAT, SOD, and 8OH-dG levels were compared between the groups . Comparep < 0.05); the CAT and SOD activities and GSH levels of the group receiving cisplatin were significantly lower (p < 0.05). MDA and 8OH-dG levels were significantly lower in the cis + sly + gal, cis + sly, and cis + gal groups compared with the group receiving cisplatin (p < 0.05). SOD activity was significantly higher in the cis + sly + gal, cis + sly, and cis + gal groups compared with the group receiving cisplatin (p < 0.05). Compared with the control group, the MDA level of the cis + sly + gal group was significantly higher (p < 0.05). SOD activity of the cis + sly + gal group was significantly higher than the group receiving cisplatin (p < 0.05). In these groups, CAT and GSH levels were high but not significant (p > 0.05).The levels of GSH, CAT, SOD, MDA, and 8OH-dG in liver tissue were discussed between groups using the data in p < 0.05), and the CAT and SOD activities of the group receiving cisplatin were significantly lower (p < 0.05). However, GSH level was low, but this value was not significant (p > 0.05). MDA and 8OH-dG levels were significantly lower in the cis + sly + gal, cis + sly, and cis + gal groups compared with the group receiving cisplatin (p < 0.05). SOD activity was significantly higher in the cis + sly + gal, cis + sly, and cis + gal groups compared with the group receiving cisplatin (p < 0.05). However, GSH level was low, but this value was not significant (p > 0.05).The levels of GSH, CAT, SOD, MDA, and 8OH-dG in kidney tissue were discussed between groups using the data below . Comparep < 0.05), and the PLT value was significantly lower (p > 0.05). Compared with the group receiving cisplatin, the WBC, RBC and HGB values of the cis + sly + gal group were significantly higher, and the PLT value was significantly lower (p > 0.05)  .p < 0.05), and albumin, total protein, testosterone, urea, AST levels were low, but this decrease was not significant (p > 0.05). Compared with the group receiving cisplatin, serum creatinine level was found to be lower, and globulin level was significantly higher in the cis + sly + gal group (p < 0.05). Compared with the group receiving cisplatin, AST, urea, and creatinine levels were significantly lower in the cis + gal group (p < 0.05)  .In the light microscopy examination, it was observed that the kidney tissues of the control, gal, sly, and gal + sly groups were in normal histological structure . Severe In the light microscopy examination, it was observed that the liver tissue of the control, gal, sly, and gal + sly groups had a normal histological structure . In ratsCisplatin (cis-diamminedichloroplatinum (II)) is a platinum-based antitumor drug used in the treatment of many types of solid malignancies, including testicular, ovarian, bladder, head and neck, and lung cancer. Although cisplatin fights cancer types, it is life-threatening due to its significant side effects. It shows serious side effects such as nephrotoxicity, hepatotoxicity, and cardiotoxicity. The decrease in GSH level and antioxidant enzymes and increase in MDA due to oxidative stress are seen as the main reason for the toxicity caused by cisplatin . As a reContributing to antioxidant defense systems in different ways, silymarin inhibits free radicals directly and the enzymes that cause these radicals to form . In a stGallic acid  is a polyhydroxy phenolic compound. It can be found in natural products such as green tea, grapes, saffron, banana, lemon, pineapple, and strawberry. It is known as a powerful antioxidant, especially due to its free radical scavenging effect , 29. In The presence of ALT and AST in the blood indicates increased permeability and necrosis of liver cells . Two difMany publications researched the effect of different substances and molecules against the toxic effect of cisplatin in the kidney and liver. In a rat study conducted in this context, undesirable pathological structures were observed in rats where cisplatin was used alone compared with the control group. Again, in the same study, when different molecular structures of gallic acid were applied, it was observed that these structures were normalized . In anotCisplatin can cause toxicity by causing physiological changes in many organs. One of the most important pathological effects of cisplatin is that it increases the oxidative stress by increasing reactive oxygen species. Silymarin and gallic acid, together or alone, can protect tissues from toxicity caused by cisplatin by reducing oxidative stress and increasing antioxidant enzymes.


To determine whether antibiotic use before chemotherapy is associated with chemotherapy responses and patient outcomes among NSCLC patients and define the optimal interval between chemotherapy initiation and antibiotic treatment.One thousand four hundred and four advanced NSCLC patients receiving first‐line platinum‐based doublets therapy were retrospectively analyzed. Kaplan–Meier curve evaluated the impact of antibiotic use and type of antibiotics on the survival of patients. The factors affect the patient's prognosis were further confirmed by Cox regression. The optimal interval between antibiotic treatment and the initiation of chemotherapy was determined by the X‐tile program.p < 0.001; Chemo‐angio:11.9 vs. 18.1 months, p = 0.012) and PFS . Cox regression analysis revealed prior antibiotic administration as an independent predictor of OS and PFS . Antibiotic usage duration  and type (PFS/OS: p < 0.001/p = 0.01) also showed significant association with patient prognosis, with calculated interval time cutoff values of 2, 4, and 2 days for fluoroquinolones, β‐lactamase inhibitors, and cephalosporins, respectively.NSCLC patients of 33.5% advanced underwent broad‐spectrum antibiotic treatment prior to chemotherapy. In the chemotherapy only (Chemo) and chemotherapy plus antiangiogenesis (Chemo‐angio) treatment groups, prior antibiotic treatment was associated with worse OS (Chemo: 13.8 vs. 17.6 months, Antibiotic use before first‐line chemotherapy was associated with poor results in advanced NSCLC patients; treatment length and type being strongly correlated with patient outcomes. Appropriate prolongation of the time between two treatments may enhance patient survival. Further prospective research is however necessary. In clinical settings, many NSCLC patients undergo antibiotic treatment prior to the initiation of chemotherapy. Previous studies have reported that antibiotic use can affect the efficacy of immunotherapeutic treatment regimens. Whether antibiotics similarly impact chemotherapy efficacy, however, remains to be established. This study compared the effects of different antibiotic treatments on patient prognosis and to define the optimal interval between Abx treatment and chemotherapy initiation. As such, many patients undergo antibiotic treatment prior to the initiation of chemotherapy.Antibiotic administration can impact gut microbiota composition.Multiple prospective and retrospective clinical studies have provided evidence that prior antibiotic therapy may impact immunotherapeutic efficacy in advanced NSCLC patients.In this study, we sought to more fully clarify how prior antibiotic treatment can impact the prognosis of patients with advanced NSCLC undergoing first‐line chemotherapy, and to more fully explore the optimal interval between antibiotic administration and chemotherapy.22.1In total, 9000 consecutive NSCLC patients treated from January 2010 to July 2018 at West China Hospital (Sichuan University), Sichuan Provincial People's Hospital, and Chengdu Jinniu District People's Hospital were retrospectively assessed for potential inclusion in this study. Individuals eligible for inclusion were patients that: (1) were diagnosed with stage IIIc or IV NSCLC without a definitive treatment option, (2) underwent first‐line platinum‐based chemotherapy with or without antiangiogenesis therapy, (3) exhibited an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0–1, and (4) did or did not receive broad‐spectrum antibiotic treatment within 1 month prior to chemotherapy. Patients were excluded from this study if they had undergone lung surgery, exhibited positive driver gene mutation status, or underwent first‐line immunotherapeutic treatment. The antibiotic prescription and other medical characteristics were extracted from the hospital information system (HIS) in participating hospitals, as we described in our previous research.This study was approved by the ethics review committee of West China Hospital, Sichuan University, which waived informed consent.2.2Parameters assessed in this study included age, gender, N stage, T stage, PS score, histology, hemoglobin, albumin, liver/ brain metastasis, chemotherapeutic regimen, and antibiotic (Abx) treatment. Those patients that underwent Abx treatment within 1 month prior to the initiation of first‐line platinum‐based chemotherapy were defined as the Abx‐treated group, and the others were defined as the Abx‐untreated group. The interval between the end of antibiotic treatment and the initiation of chemotherapy was additionally assessed. A duration of 7 days of antibiotic use was considered the standard course of antibiotic treatment, and more than 7 days was defined as prolonged antibiotic treatment.2.3PFS was defined as the duration of time between chemotherapy initiation and death or disease progression, while OS was defined as the time between treatment initiation and all‐cause death or most recent follow‐up. OS and PFS were the primary and secondary endpoints for this study, respectively.2.4p < 0.05 was the threshold of significance.Baseline characteristics were compared between groups via chi‐squared tests. Propensity score matching (PSM) was used to balance baseline characteristics of antibiotic‐treated and antibiotic‐untreated groups. Kaplan–Meier curves and the log‐rank test were used to compare patient PFS and OS. Univariate and multivariate Cox proportional hazards regression analyses were used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs). Optimal interval duration cutoff values were calculated using the X‐tile program.2.5X‐tile groups by different values as cutoffs for the target variable  and performs a statistical test on all possible groupings of the target variable. The program can choose the best split point for the data by choosing the highest χ2 value and use the log‐rank test to calculate the minimum p‐value. The color of each pixel represents the strength of the association of each cut point with survival, with red indicating a negative correlation with survival and green indicating a direct association. The horizontal x‐axis and vertical y‐axis represent all potential cut points for the low and high subsets, respectively.2.6p < 0.05 in multivariate analysis was further used to construct the nomogram model, and the predictive power of the model was assessed using calibration curve, ROC curve, risk stratification system, and decision curve analysis (DCA).The factor of 33.1β‐lactamase inhibitors .In total, 1404 patients were included in the present study, of whom 471 and 933 were included in the Abx‐treated and untreated groups, respectively. The research flowchart is shown in Figure 3.2p < 0.001; median OS: 13.7 vs. 17.7 months, p < 0.001)  and OS  were significantly reduced in the Abx treatment group relative to the untreated group  and OS   Figure . Of patip Figure . We addi) Figure .p < 0.001 and OS: p = 0.001)  were worse than those of any other patient subgroups, followed by outcomes for patients treated with cephalosporins (median PFS: 4.0 months and median OS: 15.7 months) and fluoroquinolones (median PFS: 3.8 months and median OS: 14.3 months), respectively (PFS: ) Figure . The pro3.33.3.1p = 0.001], N stage , liver metastasis , and Abx administration  were all identified as independent predictors of patient PFS , 0.817; 95% confidence interval (CI), 0.724–0.923; 3.3.2p < 0.001), histology , and Abx administration  were all identified as independent predictors of patient OS , 1.098; 95% CI, 1.015–1.187; p = 0.019], histology , and Abx administration  were all identified as independent predictors of patient PFS , 0.761; 95%CI, 0.657–0.882; 3.4.2p = 0.004) and Abx administration  were all identified as independent predictors of patient OS .The association between Abx use and patient outcomes was additionally assessed in different patient subgroups. Forest plots revealed that HRs in all subgroups were greater than 1, indicating that Abx use was an unfavorable prognostic factor in all cases Figure . These rp = 0.009) and OS .We additionally explored the relationship between antibiotic use duration and patient prognosis, revealing that prolonged antibiotic use was negatively associated with patient PFS . DCA showed that the model had good survival prediction ability.We constructed a novel nomogram model based on the results of multivariate analysis to estimate the 6‐, 9‐, 12‐, 18‐, 24‐, and 30‐month survival rates of patients  and PFS  were significantly worse in the antibiotic‐treated group than in the antibiotic‐untreated group. Also, prior antibiotic use was shown to be an unfavorable independent prognostic factor for patients .Next, we analyzed the impact of antibiotics on patients with advanced NSCLC receiving first‐line immunotherapy and found that OS  therapy.To improve the convincingness of the results and to visualize the results, we built a nomogram model using statistically significant factors in multivariate analysis. Calibration curves, risk stratification systems, ROC curves, and DCA all showed that the model had strong predictive ability.Herein, we also verified that antibiotic use affected the efficacy of immunotherapy and observed the negative effects of Abx treatment on survival outcomes for patients undergoing chemotherapeutic treatment plus antiangiogenesis treatment. We also assessed outcomes associated with Abx administration in different subgroups and consistently found that these antibiotics were linked to worse OS irrespective of treatment subgroup, with no significant differences in outcomes between the platinum‐based + etoposide and platinum‐based + vinorelbine treatment subgroups, although these subgroups were both small, limiting the power of statistical comparisons between them.β‐lactamase inhibitors and fluoroquinolones were associated with a more pronounced difference in survival outcomes among individuals undergoing chemotherapy as compared to cephalosporin treatment. And the clinical outcome of patients receiving β‐lactamase inhibitor antibiotics was the shortest among such NSCLC patients.Intriguingly, we found that different antibiotic regimens were associated with different survival outcomes in individuals undergoing first‐line chemotherapy, consistent with previous ICI‐related reports.We additionally found that the duration of antibiotic treatment was associated with NSCLC patient prognosis, in line with prior reports.After the discontinuation of antibiotic treatment, the gut microbiome can repopulate, regaining its normal immunoregulatory activity. As such, the interval between Abx treatment and anticancer treatment may be clinically relevant. Multiple retrospective studies have demonstrated that the prognosis of individuals undergoing Abx treatment within 2 months prior to immunotherapy was better than that of patients undergoing Abx treatment within 1 month prior to immunotherapy.Some may argue that establishing a causal relationship between antibiotic use and the prognosis of patients receiving chemotherapy is challenging. First of all, the reason for antibiotic use may have a significant impact on prognosis, in addition, those patients who require long courses of antibiotics or intravenous antibiotics may suffer from more severe infections, which may also potentially have a negative impact on patient prognosis. However, all patients in our study had a PS score of 0 or 1 and were considered to be able to receive platinum‐based chemotherapy. Moreover, there were no significant differences in anticancer treatment regimens between the antibiotic‐treated and antibiotic‐untreated groups. In addition, no infection‐related deaths occurred in any of the included patients, excluding confounding effects of toxic effects. Further, previous studies demonstrated that prior antibiotic therapy affected patient prognosis, whereas antibiotic use during antineoplastic therapy did not affect patient prognosis,There are multiple limitations to the present study. For one, this study was retrospective in nature and thus susceptible to selection bias. In addition, two measured variables differed significantly between the Abx‐treated and Abx‐untreated patient cohorts, potentially confounding our survival analyses. Subgroup analyses were performed in an effort to compensate for this effect. Third, we did not assess the effects of other drugs administered at baseline  and comorbidities on patient outcomes. However, the PS scores of patients included in this study were 0–1, indicating that these patients were in good condition on average. In addition, the methodology of our study is consistent with that of previous studies, and the findings echo those reported in previous studies.5Overall, our results suggest that the treatment of advanced NSCLC patients with antibiotics prior to the initiation of first‐line chemotherapy was associated with a worse patient prognosis, with these effects being most pronounced for β‐lactamase inhibitors or prolonged treatment duration. Postponing chemotherapeutic initiation in patients undergoing antibiotic treatment may thus incur survival benefits for these patients. These data serve as a reminder that antibiotics should only be administered to patients in the context of strict indications, particularly in oncology‐related clinical settings. However, additional prospective research will be essential to validate these findings.Youling Gong, Study concepts and design: Youling Gong, Literature research: Youling Gong and Ting Mei, Clinical studies: Xiaoman Tian, Ting Mei, and Rui Ao, Data analysis: Ting Mei and Youling Gong, Statistical analysis: Ting Mei and Youling Gong, Manuscript preparation: Youling Gong and Xiaoman.Guarantor of integrity of the entire study: The authors report no conflict of interest in this work.This study was approved by the ethics review committee of West China Hospital, Sichuan University, which waived informed consent.None.


Approximately 6% of those with COVID‐19 will experience cutaneous manifestations. Examining data from this cohort could provide useful information to help with the management of COVID‐19. To that end, we conducted a systematic review primarily to assess rash morphologies associated with COVID‐19 and their relationship with disease severity. Secondary outcomes include demographics, distribution, dermatological symptoms, timeline, diagnostic method and medication history. The literature was searched for all patients with skin manifestations thought to be related to suspected or confirmed COVID‐19. Patients with a history of dermatological, rheumatological or occupational skin disorders were excluded. Of the 2056 patients selected, the most common morphologies were chilblain‐like lesions (54.2%), maculopapular (13.6%) and urticaria (8.3%). Chilblain‐like lesions were more frequent in the younger population  and were strongly linked with milder disease, not requiring an admission . Conversely, acro‐ischaemia and livedo reticularis were associated with worse outcomes, including a need for ICU  and mortality . Acral lesions were the most common site (83.5%). 35.1% experienced pruritus, 16.4% had pain and 4.7% reported a burning sensation. 34.1% had asymptomatic lesions. Rash was the only symptom in 20.9% and occurred before or alongside systemic symptoms in 12.4%. 28.3% had a positive polymerase chain reaction nasopharyngeal swab and 5.4% had positive antibodies, while 21.9% tested negative and 45.1% were not tested. In conclusion, COVID‐19 causes a variety of rashes, which may cause symptoms and add to morbidity. Rash type could be helpful in determining COVID‐19 prognosis.  The World Health Organisation (WHO) declared it a pandemic in March 2020 and as of November 2021, an estimated 250 million people have been infected, resulting in over 5 million deaths.33.1https://pubmed.ncbi.nlm.nih.gov/), medRxiv (https://www.medrxiv.org/) and bioRxiv (https://www.biorxiv.org/) were searched using the search terms ‘((coronavirus) OR (SARS‐CoV‐2) OR (COVID) OR (COVID‐19)) AND ((dermatology) OR  OR (skin) OR (cutaneous) OR (rash) OR (dermis) OR (epidermis)). The search was performed on 5 February 2021 and limited to papers published up until 31 December 2020 in order to select for an unvaccinated cohort with the same or similar variants. Additional articles were obtained from reviewing bibliographies. Duplicates were removed and potential studies were selected after screening of title and abstract by two investigators independently.A systematic review of peer‐reviewed and pre‐print published literature was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines. The Medline database  Population: patients with skin changes in the context of confirmed or suspected COVID‐19 infection. Patients with cutaneous manifestations thought to be related to COVID‐19 in the absence of other more typical symptoms such as cough, rhinorrhoea, fever, and so on, were also included. (ii) Design: case reports, case series, case control studies and cohort studies.The exclusion criteria encompassed papers not in English, review articles and those with a lack of clinical data. Patients were excluded if they had a history of dermatological or rheumatological disease, including chilblains, iatrogenic lesions such as pressure sores and occupational skin disorders such as personal protective equipment (PPE) related rashes. Reactivated skin conditions, such as herpes simplex virus ulcers, were also excluded. Cases where a second pathological agent was found and those where a drug reaction was confirmed were also excluded. Efforts were made to ensure studies were not double counted and articles such as case series were screened for inclusion of cases already published or included in this review. Within each study, where some patients met the criteria for inclusion and others for exclusion, those were included in the data collection where possible. When these patients could not be reliably separated, due to issues such as the way the data were presented, the entire study was excluded.3.3Details such as digital object identifier, journal, study design, country, skin type, gender, mean age, rash morphology, distribution of lesions, dermatological symptoms, rash timing, COVID‐19 diagnostic method, COVID‐19 disease severity and recent medication changes were extracted from the selected studies as per the primary and secondary outcomes.Rash morphologies were recorded as Chilblain‐like Figure , MaculopDistribution of lesions was recorded as ‘Acral’, ‘Limbs’, ‘Head and Neck’, ‘Mucosal’, ‘Trunk’, ‘Generalized’ and ‘Hair and Nails’.Dermatological symptoms were recorded as ‘Pain’, ‘Pruritus’, ‘Burning’ or ‘Asymptomatic’.The timeline of skin changes relative to systemic symptoms was recorded as: ‘Only symptom’, ‘First Symptom’, ‘First Cluster’, ‘Rash Onset’ and ‘Rash Duration’.COVID‐19 diagnostic method was recorded as Polymerase Chain Reaction (PCR) positive, Antibody positive, Negative test, Nil test (a), Nil test (b), or method not stated.COVID‐19 severity was classified as ‘Outpatient’, ‘Inpatient’, ‘Intensive Care Unit’ (ICU) or ‘Died’ (RIP).Medication history was recorded as either ‘New Medication’ or ‘No Medication Changes’.44.1Chilblain‐like: erythematous‐oedematous, erythematous‐violaceous, blistering lesions over fingers and toes; Maculopapular: maculopapular or morbilliform rashes; Erythematous: erythematous macules or patches not fitting other morphologies; Urticarial: urticaria or wheals; Vesiculobullous: blisters, vesicles, bullae, herpes‐like, varicella‐like or papulovesicular lesions; Purpuric: purpura, ecchymoses, bruises, petechiae; Livedo reticularis: livedo reticularis, livedo racemosa, reticular purpura or mottling of skin; Acro‐ischaemia: blue/black discolouration and gangrene of fingers and toes; Erythema multiforme‐like: erythema multiforme, target‐like lesions or targetoid lesions; Oral ulcers: ulcers present on oral mucosal surfaces; Hair and Nail changes: alopecia, anagen/telogen effluvium or any nail change not attributable to any other cause; Other: skin changes not compatible with other categories.4.2Acral: lesions limited to the hands, fingers, feet and toes without involvement of other sites; Limbs: lesions limited to arms, forearms, thighs, legs or glutaeal region without the involvement of other sites; Head and neck: lesions limited to the face including forehead, cheeks, pre‐ and postauricular areas, chin and neck without the involvement of eyes, mouth, hair or other sites; Mucosal: lesions limited to oral mucosa without involvement of ocular mucosa or other sites; Trunk: lesions limited to chest, abdomen and back without the involvement of other sites; Generalized: widespread rash; Hair and nails: lesions limited to hair and nails without involvement of other sites. Patients may be included in more than one category.4.3Pain: painful sensation, not including burning, related to the skin changes; Burning: burning sensation related to the skin changes; Pruritus: itch; Asymptomatic; specific mention of asymptomatic skin lesions.4.4Only symptom: rash was the only symptom reported; First symptom: rash was the first symptom and other systemic symptoms subsequently developed; First cluster: rash occurred at the same time as other systemic symptoms; Rash onset: timing of rash relative to other systemic symptoms; Rash duration: length of time from rash onset to complete resolution.4.5PCR positive: positive result from nasopharyngeal reverse transcriptase PCR swab; Antibody positive: positive result from COVID‐19 serum antibodies including immunoglobulin A, E, G and M ; Negative test: negative result from either PCR swab or serum antibodies and no subsequent positive test. Patients who had a negative PCR swab and subsequently had positive serum antibodies were included as Antibody positive and not as Negative test. Patients with a positive PCR and antibodies were included in both categories. Nil test (a); not tested, but had COVID‐19 risk factors such as suggestive symptoms or a positive close contact; Nil test (b): not tested and had no COVID‐19 risk factors, but had a rash thought to be related to COVID‐19; Method not stated: patients stated to be diagnosed with COVID‐19, but the method is not specified.4.6Patients were counted in a single category, which was the maximum level of severity associated with that case.4.7New medication: commenced treatment for COVID‐19 or its complications prior to rash onset; No medication changes: no recent medication changes.4.8Data were recorded on a spreadsheet using the software package Numbers. Graphs were made using a combination of Numbers and Microsoft Excel.A chi‐squared test was performed for each rash morphology to examine its relationship with severity outcomes. The null hypothesis for this test was that there is no relationship between rash type and outcome and therefore, expected numbers should be evenly distributed across all four severity outcomes. A two‐tailed test was performed, with 3 degrees of freedom and a chosen alpha value of 0.05.Odds ratios (ORs), with accompanying confidence intervals (CIs), were calculated for each rash type and severity outcome using the 2 × 2 table method, with rash type and all other rashes plotted against severity outcome and all other severity outcomes.With regard to proportions, only complete data were used to account for study heterogeneity. Binomial CIs for population proportions were calculated using the Clopper–Pearson method. A direct acyclic graph (DAG) was made to illustrate causal inference and the effect of confounders on the relationship between COVID‐19 as the exposure and the outcomes of rash and severity. Subgroup analysis was performed on the confounders age and medications in an attempt to minimize heterogeneity.A sensitivity analysis was performed using only papers with non‐selective reporting of both presence and type of cutaneous signs in order to validate whether our study sample was an accurate reflection of the true population.55.1A total of 3377 papers were identified from the search, of which 2572 were from PubMed and 805 were from medRxiv and bioRxiv. Thirteen of those papers were duplicates and therefore removed. The remaining papers were then assessed further by title and abstract screening and following this, 593 articles were selected for full‐text review. Finally, 240 papers met the pre‐specified criteria and were included, comprising of 154 case reports and 86 observational studies. This is illustrated in the PRISMA flow diagram  and 855 females (49.2%). The mean age of 1285 patients was 35.3 , which is younger compared to early reviews published in China, which calculated a mean age of 49.54.6 Skin type reporting was infrequent and documented in only 353 patients. Of these patients, 293 (83.0%) were labelled ‘White’, while 22 (6.2%) were ‘Asian’, 20 (5.7%) were ‘Hispanic’, 6 (1.7%) were ‘Black’ and 1 (0.3%) was ‘Indian’. For those patients referred to as ‘Asian’, no further information was available. Two patients were stated to be Fitzpatrick type 3, while seven were type 4 and two were type 5. It was not possible to ascertain patient skin type from clinical photography of cutaneous lesions.5.3The most frequently described cutaneous manifestation was chilblain‐like lesions, which occurred in 1115 (54.2%) patients. This predominance is in stark contrast to reviews published early in the pandemic from China, which reported erythema (44.2% and 38.4%) was the most common finding, while chilblain‐like lesions were seen much more infrequently (19.7% and 10.1%).5.4Data on COVID‐19 severity was available for 1763 patients. 1272 (72.1%) had outpatient level severity, 365 (20.7%) required inpatient management, 94 (5.3%) were admitted to ICU and 32 (1.8%) died as a result of COVID‐19 or its complications. These results are summarized in Table Χ2 tests were statistically significant for each rash morphology group, indicating that there was not an even distribution of patients among the four severity outcomes in all groups. The levels of confidence for each test are included in Table 66.1This included 1150 patients, of whom 960 (83.5%) had acral involvement. Of those 960 patients, 700 had foot involvement, 71 had hand involvement and 89 had both hand and foot involvement. Trunk was the second most common site and was affected in 157 (13.7%) patients. Limbs were involved in 136 (11.8%), with 60 of those having both limbs affected, 40 having just upper limb involvement and the remaining 36 had lesions confined to their upper limbs. Forty‐nine (4.3%) had a generalized rash, while 44 (3.8%) had head and neck lesions, 30 (2.6%) had oral manifestations and 22 (1.9%) had hair and nail changes.6.2Of 700 patients with complete data, 246 (35.1%) reported pruritus, 115 (16.4%) had pain, 33 (4.7%) experienced burning and 239 (34.1%) had asymptomatic lesions. Some patients had multiple symptoms and were included in more than one category.6.3Among 508 patients with complete data, rash was the first symptom in 29 (5.7%) patients, part of the first cluster of symptoms in 34 (6.7%) patients and the only symptom in 106 (20.9%) patients. The mean onset of skin changes was 13.85 days and the mean duration was 13.16 days.6.4There was complete data available for 1083 patients. Three hundred and six 28.3%) had a positive swab, while 59 (5.4%) had positive antibodies. 488 (45.1%) did not receive testing, despite 159 of them having COVID‐19 risk factors. Two hundred and thirty‐seven (21.9%) patients tested negative. Overall data for each secondary outcome is shown on Table 8.3% had 7A total of 454 patients had recently received treatment for COVID‐19 before the development of skin signs. One hundred and nine received antibiotics, the most common of these being Azithromycin (44), Ceftriaxone (23), Tazocin (10) and Linezolid (6). Fifty‐six patients were treated with hydroxychloroquine and 43 received antivirals, including Lopinavir/Ritonavir (24), Oseltamivir (6), Favirapir (4), Darunavir, Ritonavir and Remdesevir (2 each). Twenty‐three patients received paracetamol, 19 patients were treated with corticosteroids, 21 were given heparin and 18 took supplements such as vitamin C, zinc, B12, thiamine and folate. Four hundred and twenty‐four patients had no recent medications commenced. Of the 578 patients with complete data, 154 (26.6%) took a new drug before rash onset, while the other 424 (73.4%) patients had no recent medication changes.7.1Total data for each secondary outcome are arranged by rash type in Table Rash timeline varied between morphologies for both onset and duration. This is illustrated in Figure 7.2A total of 776 patients from 11 studies were included in the sensitivity analysis, of which 59.9% were outpatients, 32.3% were inpatients, 6.9% required ICU and 0.8% died. In this cohort, maculopapular was the most common rash type (27.9%), followed by chilblain‐like (23.2%). These results are illustrated in Table 8COVID‐19 is a viral infection characterized by respiratory symptoms, fever, myalgia, fatigue and anosmia. Aside from these classic features, many systems may also be affected, including the skin. Other coronavirus syndromes, such as severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS), do not seem to result in significant skin changes. This is despite phylogenetic analysis of SARS‐CoV‐2 showing that it is closely related to both SARS‐CoV (∼79%) and MERS‐CoV (∼50%).n = 293/353) of those with information regarding race. This is likely to be reflective of the general demographics of the countries publishing the most articles. Notably, the vast majority of studies mentioning race were published from America, where 76% of people are classified as ‘White’ as per the US census.Two thousand fifty‐six patients with cutaneous manifestations secondary to COVID‐19 were identified from 240 studies. Most studies were from Europe or America, but others from Asia, South America, Australia and Africa were also included. The population had an equal proportion of each gender, but seemed to have an unequal distribution of ethnicities. Patients referred to as ‘White’ were overrepresented and accounted for 83% (Chilblain‐like lesions were by far the most common rash type seen in the main part of this review (54.2%), which is in contrast to studies published earlier in the pandemic.It is well known that worse COVID‐19 outcomes are seen in those with older ages, independent of other factors such as comorbidities.n = 505). There are also a significant proportion of patients who become infected, but remain asymptomatic for the entire disease course. A large review of high‐quality data estimated this figure to be at least one third of all infected patients. In our study, rash was the only symptom in 20.9%.Of those with full diagnostic method data available in this review, approximately a third of the patients had either a positive swab or serum antibodies, while the remainder either tested negative or were presumed to be infected. A multitude of different factors exists that affect the likelihood of a person being referred for a COVID‐19 test, aside from respiratory symptoms. In the early stages of epidemics caused by a novel infectious pathogen, testing is typically biased towards the more severe cases due to limited diagnostic capabilities.Complete data on dermatological symptoms was available for 700 patients. Pruritus was the most commonly reported symptom (35.1%), followed by pain (16.4%), then burning (4.7%). 34.1% of patients had asymptomatic skin lesions. These symptoms can carry significant physical morbidity in addition to aesthetic implications. Our knowledge of the morbidities associated with COVID‐19 is improving. For example, long COVID has been shown to cause significant and prolonged disability, and we are likely to see long‐term respiratory implications in those who suffered severe pulmonary damage.Timeline of cutaneous manifestations with respect to systemic symptoms was also examined. Oral ulcers had the earliest onset, with a mean of 3.7 days, while hair and nail changes were the latest. They were not seen until approximately 3 months after the COVID‐19 episode, which is in keeping with hair and nail life cycles. Otherwise, most rash types appeared within the ‘inflammatory phase’ window between 7 and 12 days. The morphologies associated with more severe COVID‐19 disease, namely purpura (11.7 days), livedo reticularis (14.1 days) and acro‐ischaemia (23 days), all seemed to appear later in the disease course, as did chilblain‐like lesions (15.9 days). Rash duration varied, but lasted for between 7 and 14 days for most subtypes. Urticaria resolved the quickest (6.7 days) and acro‐ischaemia lasted the longest (32 days). There was no data for hair and nail change duration. Data on duration should be interpreted with caution as it is confounded by both COVID‐19 treatment and rash specific therapies, which were not examined in detail in this review. Cutaneous manifestations were also occasionally seen as the first or only symptom. Notably, chilblain‐like lesions were the only symptom in 464 patients, far more than any other rash type, which is in keeping with its known paucisymptomatic nature and associated high rate of negative testing. The appearance of an otherwise unexplained skin change may have potential use in aiding the diagnosis of COVID‐19, but given that this study only included patients with COVID‐19 and a rash, it is unable to comment further on diagnostic value.The sensitivity analysis showed similar results in the primary outcomes to the initial study, indicating that the sample is a reasonably accurate representation of the true population. There was insufficient data on the secondary outcomes in the sensitivity analysis group to allow a fair comparison.9There are several limitations to this study. To date, there is no standardized criteria for classifying morphological rash types in COVID‐19. As a result, some patients were counted in more than one category, which may skew results. There is also a need for standardized criteria for diagnosing COVID‐19, as there was variability between methods in this review and a number of patients never received formal testing. Case reports accounted for a significant proportion of the studies included. There was likely to be some reporting bias, specifically with regard to chilblain‐like lesions due to its controversial relationship with COVID‐19. There was significant heterogeneity among studies and as a result, complete data on secondary outcomes were not always available. Patients with complete data were sampled to estimate proportions; however, this sample may not be accurately representative of the whole population. Results in these outcomes should be interpreted with caution. Confounders to primary outcome results include age, medications and comorbidities, which were not examined in this review. As studies with non‐selective reporting of cutaneous manifestations were included, this review cannot comment on the use of rash in the diagnosis of COVID‐19.10In conclusion, there are a wide range of cutaneous manifestations associated with COVID‐19. Maculopapular rash and chilblain‐like lesions were the most common morphologies, with the latter found to be strongly associated with a paucisymptomatic disease course and a low severity of COVID‐19. Conversely, skin changes such as acro‐ischaemia, livedo reticularis and purpura may be useful indicators of a higher severity of COVID‐19 disease. Rash as a clinical feature might therefore be helpful in determining COVID‐19 prognosis among those with skin changes, but this is confounded by age, medications and comorbidities. These cutaneous manifestations can also cause symptoms such as pain, burning and pruritus, which carry a morbidity burden and should not be overlooked. While this study has several limitations, including significant heterogeneity, the data presented is still useful in progressing the understanding of COVID‐19, specifically in the context of dermatology. The skin has the potential to play an important role in multiple aspects of the diagnosis and treatment of COVID‐19.The authors declare that there are no conflict of interests.Zack Holmes: Conceptualization; data curation; formal analysis; investigation; methodology; project administration; writing ‐ original draft; writing – review & editing. Ashling Courtney: Data curation; methodology; writing – review & editing. Marc Lincoln: Formal analysis; methodology; writing – review & editing. Richard Weller: Supervision; writing – review & editing.