This review will address the place of innovative, non-chemotherapy, non-CAR-T targeted therapies in the treatment of Acute Lymphoblastic Leukaemia (ALL), focusing on their use in the hematopoietic stem cell transplant (HSCT) context. The focus will be on the agent with the most experience to date, namely the bispecific T-cell engater (BiTE) blinatumomab, but references to antibody-drug conjugates (ADCs) such as inotuzumab ozogamicin and monoclonal antibodies such as daratumamab will be made as well. Specific issues to be addressed include: (1) The use of these agents to reduce measurable residual disease (MRD) prior to HSCT and their potential for improved transplant outcomes due to reduced toxicity compared to traditional chemotherapy salvage, as well as potentially increased toxicity with HSCT with particular agents; (2) the appropriate sequencing of innovative therapies, i.e., when to use BiTEs or antibodies versus CARs pre- and/or post-HSCT; this will include also the potential for impact on response of one group of agents on response to the other; (3) the role of these agents particularly in the post-HSCT relapse setting, or as maintenance to prevent relapse in this setting; (4) special populations in which these agents may substitute for traditional chemotherapy during induction or consolidation in patients with predisposing factors for toxicity with traditional therapy , or those who develop infectious complications precluding delivery of full standard-of-care (SOC) chemotherapy during induction/consolidation ; (5) the evidence we have to date regarding the potential for substitution of blinatumomab for some of the standard chemotherapy agents used pre-HSCT in patients without the above risk factors for toxicity, but with high risk disease going into transplant, in an attempt to decrease current rates of transplant-related mortality as well as morbidity; (6) the unique toxicity profile of these agents and concerns regarding particular side effects in the HSCT context. The manuscript will include both the data we have to date regarding the above issues, ongoing studies that are trying to explore them, and suggestions for future studies to further refine our knowledge base. Relapse of B-cell precursor acute lymphoblastic leukaemia (BCP-ALL) in the paediatric population is relatively uncommon, with an incidence of about 15%. However, children with relapsed disease have a median 5-year survival rate of 25-50% (2/day. The recommended phase 2 dose (RP2D) was determined as 5 or 15 μg/m2/day . Of the 70 patients treated with the recommended dose, 39% achieved a complete remission (CR) within the first two cycles of blinatumomab, with 52% of the responders achieving complete measurable residual disease (MRD) negativity. Thirteen patients went on to allogeneic HSCT in blinatumomab-induced remission, seven of whom had been transplanted previously. The study showed that blinatumomab had antileukaemic activity and induced remissions across all age groups, including in patients with unfavourable cytogenetics . Eligible patients were <18 years of age and had R/R BCP ALL with >25% bone marrow blasts at enrolment. Disease status was primary refractory, patients in first relapse after a full salvage induction regimen, in second or later relapse, or in any relapse after allogeneic HSCT. Forty-nine patients were treated in phase I and 44 patients in phase II. In phase I, the maximum tolerated dose (MTD) of blinatumomab was determined to be 15 μg/mIn the blinatumomab expanded-access program , patients with a second or later relapse, any relapse after allogeneic HSCT, or who were refractory to other treatments, received blinatumomab for 1–2 induction cycles with the option to receive up to three additional blinatumomab consolidation courses. In total, 110 patients were enrolled. At screening, 11% of all patients had <5% bone marrow blasts, while the remained had ≥5%. Sixty-nine of the 110 study patients (63%) had CR as best response in the first two cycles; of these, 45 (65%) proceeded to HSCT. MRD response was dependent on the pre-infusion blast count, being 47 and 92% for patients with ≥5 or <5% blasts, respectively  with B-cell ALL from five North American paediatric centers who received blinatumomab in CR  due to persistent MRD [0.01-2.2% by flow cytometry (FCM)] prior to HSCT. Fourteen of the 15 patients had MRD reduced to undetectable levels and were able to proceed to HSCT without significant delay or organ toxicity . Overallp = 0.03); all statistics were descriptive, but as a whole they support the positive benefit: risk assessment regarding the utility of blinatumomab in the treatment of high-risk B-ALL in first relapse.Finally, the North American Children's Oncology Group (COG) designed a randomised trial for children and AYA to more rigorously assess blinatumomab in patients of this age group with a first high-risk B-ALL relapse . Enrollmp < 0.001). All secondary and exploratory outcomes were in favour of blinatumomab.Locatelli et al. similarly randomised 108 children from age 28 days to 18 years with high-risk B-ALL in first relapse to either one cycle of blinatumomab or one cycle of chemotherapy as the third consolidation element . This stIn summary, current evidence points toward the efficacy and manageable toxicity of blinatumomab in paediatric patients with BCP-ALL. This is specifically the case in the context of MRD-positive disease prior to HSCT, and as a substitution for single chemotherapy blocks to induce deeper remissions and increase eligibility for subsequent HSCT.p < 0.0001; INO-VATE trial,  was found to be the RP2D in children as well. Responses included 15 patients (60%) who achieved CR at one of the 2 dose levels studied, 1 patient who achieved a CR with incomplete platelet recovery (CRp), and 4 patients who achieved a CR with incomplete haematologic recovery (CRi); sixteen of the 19 responders for whom MRD data were available achieved MRD-negativity. Three patients treated at the RP2D or the dose level below experienced hepatic DLTs, prompting implementation of a protocol amendment regarding transaminase monitoring and stricter dose delays; no further hepatic DLTs occurred at the RP2D. One patient at experienced prolonged haematologic recovery at the RP2D. Notably, there were no cases of hepatic veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) reported during treatment with InO, nor in the seven patients who proceeded to HSCT after InO therapy. However, two patients treated with InO subsequently experienced VOD/SOS during treatment with multi-agent chemotherapy upon disease relapse.InO is a humanised monoclonal ADC targeting CD22-positive cells; it delivers the potent cytotoxin calicheamicin directly to leukaemic blasts. InO has demonstrated impressive single-agent activity in the adult setting [response rate 78.4 vs. 28.1% Brivio and colleagues retrospectively reviewed the data on 15 patients under 3 years of age treated internationally with InO for the same indication. Seven patients achieved CR (47%) and one became MRD-negative after MRD-positivity. The 6-month OS was 47% [95% confidence interval (CI): 27-80%]; two patients developed VOD/SOS after transplant, including one patient for whom this was fatal  with R/R ALL treated on a paediatric InO compassionate use (CU) programme. Complete responses were seen in 67% of the patients who were treated for overt relapse, and 71% of responders achieved MRD-negativity in the bone marrow, in most patients after the first cycle . The admBearing in mind the different treatment contexts, it is noteworthy that in the adult experience of InO, while demonstration of clinical benefit was shown based on durable CR and MRD-negative CR rates in the INO-VATE ALL trial, the analysis of OS did not meet the pre-specified boundary for statistical significance. Additionally, the US Food and Drug Administration (FDA)-approved label for relapsed/refractory adult B-ALL included a boxed-warning for hepatotoxicity, including fatal VOD as well as post-HSCT non-relapse mortality in the InO arm.In line with the blinatumomab and InO data summarised above, Spanish data in 29 children indicate similar remission rates of 47.6% with either blinatumomab or InO, and reduction of MRD while avoiding further toxic chemotherapy prior to HSCT .In summary, InO is a promising drug that is currently best studied in the setting of residual MRD or refractory disease. With current HSCT strategies, preventive supportive care and close monitoring according to paediatric guidelines, VOD/SOS might well be manageable in children. A systematic and prospective phase II study in children is currently ongoing , which is investigating InO both as monotherapy and in combination with chemotherapy for high-risk and very-high risk relapsed BCP-ALL in patients ≥ 1 to <18 years of age at the time of enrollment. Another COG study (NCT02981628) is investigating InO in combination with a chemotherapy backbone in patients 1-21 years of age with R/R BCP-ALL. The upcoming IntReALL trial may plan InO as an induction therapy in patients with high-risk relapsed B-ALL.A recent case report describes an 11-year-old child with primary refractory ALL in whom repeated cycles of blinatumomab and InO allowed achievement of molecular remission, serving as bridging therapy to a successful HSCT .Brethon et al. reported an interesting case report where blinatumomab and gemtuzumab ozogamicin were combined in a 4-month old child with KMT2A-rearranged, mixed-phenotype leukaemia . SubsequNovel targeted regimens are evolving in diseases mostly affecting adults, such as chronic lymphocytic laeukemia (CLL), in which combinations of targeted biologic therapies  can replace traditional chemotherapy . PatientAlthough the COG study  failed tde novo very high-risk disease and compared to other strategies, including blinatumomab and InO. Moreover, it necessitates patient-specific manufacturing processes that can take precious time.Thus, blinatumomab appears to be a highly-promising choice for consolidation therapy before allogeneic HSCT in children and AYAs with a first relapse of B-ALL. Unlike CAR-T cells, blinatumomab is readily available as a pre-manufactured drug, an important advantage in these clinical scenarios, as children with relapse often require immediate treatment. CAR-T cell therapy shows promising results in children with multiply relapsed or refractory disease. However, this therapy has yet to be rigorously evaluated in patients in first relapse or with InO is an off-the-shelf drug. It is convenient to administer as a short intravenous infusion in contrast to the continuous 28-day infusion of blinatumomab, and therefore it can be combined with other therapies, as is currently investigated in the paediatric ITCC-059 study. However, the risk of developing VOD/SOS during subsequent treatment warrants further investigation in the pre-HSCT setting, especially in children.To date, there are insufficient data directly comparing the various non-chemotherapeutic strategies prior to HSCT to decisively clarify whether blinatumomab, InO or even CAR-T cell therapy are the optimal pre-HSCT therapy. Specifically, the decision to reserve the use of CARs for post-HSCT relapse or to use them in the relapse setting to achieve remission prior to allogeneic HSCT is a subject of considerable debate in the paediatric laeukemia community. Factors influencing the decision whether or not to consolidate CAR-T cell therapy with HSCT are discussed in detail in the companion paper by Buechner and colleagues in this same Frontiers in Paediatrics supplement. Of note, if CAR-T is being used solely as a “bridge” to HSCT- to induce remission pre-HSCT rather than as definitive therapy- it remains to be seen whether blinatumomab, given the advantages discussed above, might be a more appropriate choice.The administration of blinatumomab in CR1, as a substitute to standard chemotherapy or even bridging to transplant is currently being evaluated in several trials . Extrapolating data from the trials in ALL in first relapse predicts a high likelihood that blinatumomab can find its place in this setting as well, potentially lowering MRD with less associated toxicity and possibly improving HSCT outcomes in this population.While mainly studied thus far in the R/R population, ongoing studies have capitalised on the relatively decreased toxicity profile seen with blinatumomab to explore its role in the treatment of subpopulations of patients with ALL for whom standard chemotherapy is particularly toxic. Two specific historic subpopulations are patients with Trisomy 21  and infants, although patients who develop infectious complications that may interfere with their ability to tolerate standard chemotherapy are relevant candidates as well.In addition to a higher risk of relapse, patients with DS have been shown to have an increased risk of treatment-related mortality with traditional induction and consolidation chemotherapy , 16, sucThe data to date on the use of blinatumomab in patients with DS is limited to mostly case reports –20. At oWhile it is premature to make any predictions regarding the safety or efficacy of blinatumomab in patients with DS, the results of these studies will inform decision-making for this cohort of patients and give a more objective answer as to whether the use of blinatumomab has the potential to improve their outcomes by decreasing treatment-related mortality without compromising efficacy. These studies will also provide a more granular toxicity profile for patients with DS who are treated with these agents, which could potentially allow for risk-mitigation strategies that will further enhance the safety of their use in this fragile population. Finally, if the use of blinatumomab in patients with DS is in fact shown to allow for an increased number of these patients to achieve an MRD-negative state with less toxicity than traditional chemotherapy, this could potentially affect the HSCT outcome of these patients as well, given the data referred to above  suggestiALL in patients under 1 year of age, so-called “infant ALL,” has a particularly poor prognosis, especially for the approximately 75% of patients who have a KMT2A rearrangement, for whom the expected 5-year EFS is as low as 35% –23. Even9/L, or had a poor prednisone response, and medium-risk (MR) if they had a KMT2A-rearrangment without the other high-risk features. The protocol randomised MR and HR patients to a course of post-induction “lymphoid” therapy , or two courses of post-induction “myeloid” therapy . Patients in all risk-categories proceeded to two further courses of identical therapy before entering maintenance, with the exception of those proceeding to HSCT, who did so after the first identical cycle. Criteria for HSCT were all HR patients, and during the course of the study, this was extended as well as to MR patients with an MRD of ≥10−4 at the end of that cycle. The study had 80% power to detect a DFS difference of 16% at 3 years, assuming 41% DFS in the control arm, with an alpha of 0.05; the study failed to show a difference in DFS between the randomised arms, with 4- and 6-year DFS of 42.2% [standard error (SE) 3.9] and 39.3% (SE 4), respectively, in the “myeloid treatment” arm, and 37.8% (SE 3.9) and 36.8% (SE 3.9) in the “lymphoid treatment” arm. OS at 6-years was similar in the two arms, being 54.4% (SE 4.0) in the “myeloid” arm and 47.1% (SE 4.2) in the “lymphoid” arm, with a nominal p-value of 0.2706. Finally, cumulative incidence of relapse (CIR) at 6-years was similar between the arms , as were the rates of deaths in continuous complete remission . However, relevant to the focus of this review, there was deviation from randomisation and outcomes for those patients who underwent HSCT in this study. Specifically, although all HR patients were to proceed to HSCT in CR1 after cycle 3 (lymphoid arm) or 4 (myeloid arm), only 76 of the 143 patients in the HR subgroup actually proceeded to transplant in CR1, due to earlier events in the 54 remaining patients, mostly relapses (numbers not specified). For the 76 patients who proceeded to HSCT, the 4-year DFS was only 44%, comprising 26 (34.2%) patients who relapsed, 14 (18.4%) who died in CR due to HSCT-related toxicity, and two patients who developed a second malignancy. Once the protocol was amended to include HSCT recommendations for MR patients who did not achieve MRD-negativity, only 16 of the 23 patients who met these criteria proceeded to HSCT, and the 4-year DFS in this cohort was only 18.8%. It is notable that the death rate in CR post-HSCT dropped from 26% (N = 50) in those undergoing HSCT between 2006 and 2011, who received busulfan, cyclophosphamide and melphalan conditioning, to 5% (N = 61), in those undergoing HSCT with busulfan, fludarabine, treosulfan, and thiotepa conditioning. Interestingly, in the patients treated with “myeloid” therapy, the death rate in CR was similar overall (10.1%) to that of those treated with “lymphoid” therapy (8.1%), but more of these deaths were considered related to HSCT in the latter (5%) than in the former (3%). This suggests that intensive therapy followed by HSCT in these patients carries with it a not-insignificant risk of mortality that may be related to the intensity of therapy required in these patients.In the recently published Interfant-06 protocol , infantpost-hoc analyses are limited, the lack of improvement in outcomes, the limitations of HSCT in either treatment arm, and the high number of relapses and toxic-deaths in this large study of patients with infant ALL, raises the question as to whether in this population, less-intensive, targeted therapy might improve outcomes overall and potentially also outcomes with HSCT in relevant subpopulation(s). This is the subject of a current pilot study (see below).Although Experience with blinatumomab in infants is limited. The largest cohort of patients reported to date was a retrospective study done in the UK and the Republic of Ireland . They deOther case reports with even smaller numbers of patients yield similar outcomes to the study outlined above .To allow for a more comprehensive assessment of the safety and efficacy of blinatumomab in infant ALL, the goal of the ongoing Interfant pilot study, Trial NL5993  is to test the feasibility of adding blinatumomab to the Interfant-06 protocol. The group states that “the toxicity and safety data of this pilot study will directly influence the drug choice and schedule given to infants in the worldwide collaborative COG/JPLSG/Interfant group trial” . Of note, inclusion criteria require that patients enrolled in this study are in CR post-induction ; since iA less well-defined niche in which blinatumomab may be especially suitable is on a case-by-case basis for patients in whom opportunistic infection or other organ toxicities preclude the use of standard chemotherapy. Because this population is not rigidly-defined, the data in these clinical contexts are limited to specific cases within a series or case reports, and the literature is scattered with accounts of patients (often in the R/R setting) in whom blinatumomab was administered to allow for disease control in the face of potentially fatal invasive fungal infections (IFI), including sinus and orbital zygomyces infection and pulmonary fungal infection . At one During the last decade, several groups have investigated the prognostic impact of post-transplant MRD in paediatric ALL; MRD after HSCT is a dynamic process and variations of MRD over time are important in predicting outcome. While high levels of post-transplant MRD positivity are strongly predictive of disease recurrence, low level MRD values, especially if detected early after HSCT, are not invariably associated with relapse . By contThere is thus great interest in the application of blinatumomab and InO to eliminate detectable MRD following HSCT patients with BCP-ALL, in an attempt to prevent overt disease relapse. Furthermore, these approaches are particularly attractive as maintenance therapy, irrespective of MRD-results, for patients with disease deemed at high-risk of relapse, such as those with pre-HSCT MRD positivity or unfavourable cytogenetic features. Many groups are investigating the use of blinatumomab post-HSCT to consolidate remission status.In the ALL SCTped 2012 For Omitting Radiation Under Majority Age (FORUM) Add-on Study, paediatric patients who are MRD-positive before HSCT or who become MRD-positive after HSCT are candidates to receive blinatumomab after tapering/discontinuation of immune suppression (NCT04785547). The University of British Columbia is conducting a trial in children and adults with B-cell ALL based on sequential post-transplant MRD-testing followed by blinatumomab administration in case of detectable MRD (NCT04044560). The Medical College of Wisconsin is evaluating blinatumomab in children and AYAs with high-risk B-ALL in two different experimental arms: patients who are MRD-negative by flow cytometry (FCM) and high-throughput sequencing (HTS) before transplant will receive reduced-intensity conditioning, while patients with with MRD-negativity by FCM but MRD-positivity by HTS will undergo myeloablative, TBI-based conditioning. All subjects will receive a T-cell receptor (TCR) α/β T-cell- and B-cell-depleted HSCT followed by blinatumomab continuous infusion starting from day 100 after-HSCT (NCT04746209).The MD Anderson Cancer Center is investigating the use of blinatumomab as a maintenance strategy following allogeneic HSCT in children and adults (NCT02807883). Preliminary results in adults with high-risk B ALL have shown that blinatumomab started within 3 months post-HSCT is well-tolerated. Among the 12 patients treated, none of the 8 subjects with MRD negativity before treatment initiation has relapsed. By contrast, all subjects with positive post-transplant MRD progressed to overt disease recurrence. Of note, the 4 patients who relapsed had a lower CD8/CD4 ratio and higher expression of checkpoint proteins and molecules [particularly programmed death 1 (PD1) and T-cell immunoreceptor with Ig and ITIM domains (TIGIT)] compared to non-progressors .In the context of allogeneic HSCT, it has been hypothesised that blinatumomab could potentially induce a broader GvL effect by inducing polyclonal donor T-cells expansion, reactivating donor memory-T cells and suppressing B regulatory cells , 43. ThiEarly administration of blinatumomab for detectable MRD after transplant has the advantage of exploiting the anti-leukaemic effect of blinatumomab in the context of low disease burden, thought to be associated with increased response rates , and T-cLike blinatumomab, pre-emptive administration of InO is also under investigation as a strategy to reduce leukaemia relapse after transplantation in both children (NCT03913559) and adults . As reviewed above, of particular concern using InO after HSCT is the potential for increased VOD/SOS risk [Brivio et al., 2021, . SimilarIn conclusion, available data are scarce and do not allow one to draw any definitive conclusions regarding the role of pre-emptive blinatumomab or InO administration after HSCT. Although prophylactic immunotherapy is an intriguing strategy to optimise the outcome of HSCT in B-ALL, results of ongoing clinical trials, preferably those that include prospective monitoring of pre- and post-transplant MRD, are much awaited to clarify the efficacy and potential drawbacks of each strategy and to better identify those patients who are likely to most benefit from these approaches.Some of the critical unanswered questions with regard to blinatumomab and InO pertain to the presumed lower toxicity of these classes of agents in comparison to traditional chemotherapeutic agents. While caution must be exercised when comparing even therapeutics with similar mechanisms in different diseases, in general the InO story is vaguely reminiscent of the history of gemtuzumab ozogamycin (GO), an anti-CD33 targeting ADC linked to calcheamicin. While initially approved in 2000 for the treatment of older patients with relapsed AML, both lack of confirmation of clinical benefit as well as safety concerns, including treatment-related mortality (induction deaths) and VOD/SOS, were associated with its market withdrawal 10 years later . ExtensiThe results of ongoing studies will be crucial to inform decision-making in this arena, in particular whether these therapies can produce improved efficacy when given prior to allogeneic HSCT without untoward toxicity, such as VOD/SOS or GVHD, which will lead to enhanced EFS and OS in the long run. Until further, extensive data in children and adults are available, the potential for unique severe toxicities from these therapies, as well as the potential for improved efficacy with their use, should inform the risk-benefit calculus when making treatment decisions between InO, blinatumomab, and CAR-T cell therapies. Finally, we look forward to results of ongoing studies in the post-HSCT application of these therapies in the maintenance or relapse settings to appraise their relevance and potential in improving outcomes for paediatric patients undergoing HSCT for ALL.KK, MA, JB, and AK contributed to conception and design of the analysis. KK, MA, and AK wrote sections of the manuscript. All authors contributed to manuscript revision, read, and approved the submitted version.Author JB has received personal fees, advisory board/steering committee honoraria, and non-financial support from Novartis; and advisory board honoraria from Pfizer, Kite, and Janssen. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Little information has been reported about the impact of the COVID-19 pandemic in Philadelphia-negative chronic myeloproliferative neoplasms (MPN). In this review, we summarize the knowledge about MPN clinical management, including cytoreductive and antiplatelet/anticoagulant therapy, thrombotic risk, prognosis, and vaccination strategies at the time of COVID-19.An outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) started in December 2019 in China and then become pandemic in February 2020. Several publications investigated the possible increased rate of COVID-19 infection in hematological malignancies. Based on the published data, strategies for the management of chronic Philadelphia-negative chronic myeloproliferative neoplasms (MPNs) are provided. The risk of severe COVID-19 seems high in MPN, particularly in patients with essential thrombocythemia, but not negligible in myelofibrosis. MPN patients are at high risk of both thrombotic and hemorrhagic complications and this must be accounted in the case of COVID-19 deciding on a case-by-case basis. There are currently no data to suggest that hydroxyurea or interferon may influence the risk or severity of COVID-19 infection. Conversely, while the immunosuppressive activity of ruxolitinib might pose increased risk of infection, its abrupt discontinuation during COVID-19 syndrome is associated with worse outcome. All MPN patients should receive vaccine against COVID-19; reassuring data are available on efficacy of mRNA vaccines in MPNs. Alpha and beta Coronaviruses (CoVs) are a subfamily of large and enveloped viruses that are known to infect humans, mainly through respiratory transmission ,2. SeverIn December 2019, a novel coronavirus was identified to be responsible for unidentified pneumonia outbreaks in Wuhan, Hubei Province, China . Since tThe incubation period of COVID-19 is between 1 and 14 days, mostly between 3 and 7 days. Transmission occurs primarily via respiratory droplets and close contacts. The SARS-CoV-2 infection may be responsible for different outcomes ranging from asymptomatic infection (6.4%), mild to moderate cases (79.6%), severe (5.3%), critical (7.3%) and fatal cases (1.4%) . H. H112]. In MPN patients who are SARS-CoV-2 negative during the pandemic, ruxolitinib should be started or continued with no modifications according to guidelines. A negative SARS-CoV-2 swab test is generally not requested before ruxolitinib start; however, obtaining the COVID-19 status might be useful. There is also no indication to modify ruxolitinib doses in patients with asymptomatic/mild COVID-19. However, a dose reduction of ruxolitinib may be temporarily performed to reduce drug–drug interactions worsening hematology parameters or patients’ clinical status. To note, the discontinuation of ruxolitinib in MPNs with COVID-19, outside a clear indication, seems associated to a worse outcome and is discouraged .Vaccines are considered the most promising approach to prevent SARS-CoV-2 infection and control the pandemic . SARS-CoAccording to the Danish National Patient Registry, the reported incidence rate of thromboembolic events among vaccinated Europeans is not increased relative to the expected number estimated from incidence rates from the entire Danish population . HoweverCOVID-19 elicits an impaired antibody response against SARS-CoV-2 in patients with hematological malignancies . Hence, In a small cohort of MPN patients, those receiving treatment with peg.interferon had the highest serological response in comparison with ruxolitinib or hydroxyurea. Notably, only two-thirds of the patients not receiving cytoreduction seroconverted .All patients with MPN must receive vaccination against COVID-19. No specific MPN-related risks associated with vaccination are known. There are reassuring data concerning efficacy of COVID-19 mRNA vaccine in the general MPN population; however, the use of ruxolitinib could impair the seroconversion after vaccination.Telemedicine is the use of telecommunications technology as a tool to deliver health care ,154,155.The COVID-19 pandemic further highlighted how health care facilities can spread the virus and focused attention on new models of care that reduce in-person contacts to lessen the transmission of the virus and protect medical practitioners from infection ,159,160.During the first pandemic wave, the Italian GIMEMA Working Group on MPNs launched a survey that was responded by 98 Italian Hematologists with specific focus on clinical management of MPNs during the pandemic. Over 80% medical visits were converted into telehealth in 19.8%, 38% and 50% of MF, PV and ET patients, respectively . In addip < 0.001), were under active therapy (p = 0.03) and enrolled into a clinical trial (p < 0.001) [A recent analysis concerning the use of telemedicine at the Institute of Hematology “L. and A. Seràgnoli”, Bologna, Italy, showed that during the first pandemic wave (9 March–4 May 2020) a total of 365 out of 489 (74.6%) visits were converted to telephone appointments. Compared to patients receiving a telephone contact, the patients who required in-person visits were more frequently affected by MF (< 0.001) . Overall< 0.001) . However< 0.001) .Whether and to what extent telemedicine affected patient outcome in terms of blood count control, symptom control and complications, remains to be clarified.During the COVID-19 pandemic, the integration of telemedicine and virtual care into the healthcare system emerged as an approach to maximize the efficiency of healthcare delivery by promoting social distancing, reducing face-to-face contacts and virus transmission and avoiding cancelling or postpone outpatient medical visits.However, telemedicine seems to be more feasible and promising in ET and PV patients with stable disease who are not enrolled into investigational trials. In addition, the presence of a dedicated medical team that can guarantee a high quality of medical care and the cooperation of patients and caregivers may significantly improve the quality of telemedicine. Future studies are required to assess whether telemedicine may negatively affect disease control and MPN-related complications.The COVID-19 pandemic induced a rapid reorganization of healthcare facilities and greatly influenced the management of patients with cancer, who had to face a reduced possibility to perform laboratory tests and hospital visits; some specific therapies have been interrupted or postponed. MPNs and particularly MF patients may be at increased risk of severe SARS-CoV-2 infection. Differently, ET patients are at higher risk of thrombosis. There is uncertainty in the definition of the specific infectious risk related to their disease and to their chronic treatments. In addition, management of thrombotic and hemorrhagic risk may be challenging. The clinical evidence collected to date provides guidance for a proper management of MPN patients during the pandemic (summarized in Overall, the experience gained in this pandemic year has also represented an opportunity for improvement in some areas, including the development of telemedicine, the expansion of international cooperation and the acceleration of approval pathways and implementation of clinical trials.


There has been a rise in the prevalence of non-alcohol fatty liver disease (NAFLD) due to the popularity of western diets and sedentary lifestyles. One quarter of NAFLD patients is diagnosed with non-alcoholic steatohepatitis (NASH), with histological evidence not only of fat accumulation in hepatocytes but also of liver cell injury and death due to long-term inflammation. Severe NASH patients have increased risks of cirrhosis and liver cancer. In this review, we discuss the pathogenesis and current methods of diagnosis for NASH, and current status of drug development for this life-threatening liver disease. There has been an increased interest in non-alcoholic fatty liver disease (NAFLD), and its advanced stage, non-alcoholic steatohepatitis (NASH) because of their increasing impact on global health . In the NASH is strongly associated with overweight or obesity and metabolic syndromes , 10. RecAt present, steady progress in clarifying the pathogenesis of NASH has been made, leading to the identification of therapeutic targets for drug development. However, there is currently no FDA-approved drug that can cure NASH. In addition, the lack of precise predictive biomarkers limits early diagnosis of NASH. Liver biopsy remains the gold standard for diagnosis of NASH. This review focuses on discussing the risks for NASH pathogenesis, current development of biomarkers, and therapeutic target identification for drug development.The “two-hit” theory for the development of NASH was first proposed more than two decades ago . The theFibrosis in the liver and hepatocyte injury and death are the key features that distinguish NASH from isolated steatosis , 33. It hi macrophages and Ly-6Clo macrophages , MMP12 and MMP13 (lo macrophages express chemokine (C-X3-C motif) receptor 1 (CX3CR1), and because its ligand1 (CX3CL1) is mainly expressed in HSCs, CX3CL1-CX3CR1 interaction negatively regulates inflammatory properties in macrophages within the liver (hi macrophages) recruitment induced by Toll-like receptor 4 (TLR4) signaling  suggest that polymorphisms in patatin-like phospholipase domain-containing 3 (PNPLA3) and transmembrane 6 superfamily, member 2 (TM6SF2) promote the development of NASH . ParticuEpigenetic mechanisms are special genetic regulations without any change in gene sequence in the genome but with different modifications, such as DNA methylation, histone modification, and non-coding RNAs . By analConsumption of a high-calorie diet with high fat and high sugar (western diet) results in weight gain and is the initial event for the development of fatty liver –127. ParEscherichia, where patients with advanced fibrotic NASH or cirrhosis have dramatically increased proportions of Bacteroides and Ruminococcus  is a non-invasive marker of liver fibrosis , and serMost NASH patients are obese. The first and simplest management against NAFLD or NASH is to make lifestyle modifications . ThroughIn addition to lifestyle modifications, there are several therapeutic targets that are under clinical trials . The mosOxidative stress plays an essential role in the development from isolated steatosis to NASH . Anti-oxGlucagon-like peptide 1 (GLP-1) is essential for glucose homeostasis . GLP-1 aPeroxisome proliferator-activator receptors (PPARs) are a group of nuclear receptors that play a critical role in intracellular lipid metabolism . ExtensiFarnesoid X receptor (FXR) is a master regulator of hepatic triglyceride and glucose homeostasis . ObetichNASH is a disease with inflammation and fibrosis. Chemokine receptor 2/5 (CCR2 and CCR5) are commonly increased in the liver from NASH patients. Cenicriviroc (CVC), a C-C motif chemokine receptor 2/5 (CCR2/5) antagonist, was developed to target inflammation . In NASHGalectin-3 protein expression is essential for the development of hepatic fibrosis, which is significantly increased in NASH liver . In miceTo improve inflammation and fibrosis in NASH, many therapeutic targets have been tested. The inhibitors of apoptosis signal-regulating kinase 1 (ASK1), a serine/threonine kinase, have been shown to significantly improve fibrosis in NASH animal models . SelonseStudies between microbiome and NAFL/NASH are relatively nascent, but the consensus is that dysbiosis leads to increased intestinal permeability, which may increase NAFL/NASH progression . Thus, dAlthough many potential candidates for the treatment of NASH are under phase II and III clinical trials as discussed above, no drug has yet been approved by the FDA. In addition to the discovery of novel promising targets for clinical testing, existing drugs like piloglitazone and statins used for the treatment of diabetes and CVD diseases can also be viable therapeutic options for NAFL/NASH. Furthermore, antioxidant vitamin E can be a beneficial supplement for NAFL/NASH patients.Considering NAFLD is closely associated with metabolic dysfunction, metabolic dysfunction-associated fatty liver disease (MAFLD) may better describe the disease than NAFLD . The laclo macrophages to treat NASH.Non-invasive diagnosis approaches can primarily detect hepatic steatosis sensitively but struggle to detect fibrosis, meaning the diagnosis of NASH still requires invasive liver biopsy. Development of non-invasive methods that can sensitively and accurately diagnose NASH is currently ongoing and such methods may be available in the future. At present, because of the absence of any existing FDA-approved medication for the treatment of NASH, an effective clinical pharmacotherapy is urgently needed for advanced NASH. For mild NASH, the most healthy and effective treatment is through management of diet and lifestyle. NASH fibrosis regression can occur with 10% weight loss, but such weight loss is difficult to achieve. In addition, NASH is commonly associated with diabetes, meaning drugs that target diabetes may have potential for treating NASH. In addition, the development of drug targets on gut microbiota may be a novel direction in the coming decades, because accumulating evidence shows microbiota dysbiosis is one of the critical causes of NASH through the gut-liver axis. Alternatively, the development of pharmacological interventions targeting the polarization of M2 Kupffer cells during the early stages of NASH may become an attractive strategy for reducing inflammation and hepatocyte injury. Similarly, in monocyte-derived macrophages, it is attractive to develop pharmacological interventions that target the polarization of pro-restorative Ly-6CGreat developments in NASH pathogenesis, diagnosis and treatment have been achieved in the past decades. This review discusses factors that may induce NASH, non-invasive methods for NASH diagnosis, and potential pharmaco-therapeutic options to resolve NASH. Dietary factors are a major cause for NAFLD that may further develop into NASH, particularly for people under long-term high fat and high sugar consumption who are obese or overweight. Body weight loss is beneficial for early-stage NASH. Accurate and sensitive non-invasive diagnosis methods for NASH are needed to replace invasive liver biopsy. Although no FDA-approved drug is available for NASH, many clinical pharmacotherapies are under phase II or phase III clinical trials. Moving forward, more potential NASH targets will likely be identified, offering more opportunities to discover effective and specific drugs to treat and resolve NASH.BZ, S-LC, and HC wrote the manuscript. JL and KL edited the manuscript. HW and KC critically read the manuscript. All authors contributed to the article and approved the submitted version.This work was supported in part by NIH Grants Nos. R01HL093242, R01HL137229, R01HL133216, and R01HL156362 to HC.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Acquiring a reliable estimate of glomerular filtration rate (eGFR) at the emergency department (ED) is important for clinical management and for dosing renally excreted drugs. However, renal function formulas such as CKD-EPI can give biased results when serum creatinine (SCr) is not in steady-state because the assumption that urinary creatinine excretion is constant is then invalid. We assessed the extent of this by analysing variability in SCr in patients who visited the ED of a tertiary care centre.Data from ED visits at the University Medical Centre Utrecht, the Netherlands between 2012 and 2019 were extracted from the Utrecht Patient Oriented Database. Three measurement time points were defined for each visit: last SCr measurement before visit as baseline (SCr-BL), first measurement during visit (SCr-ED) and a subsequent measurement between 6 and 24 hours during admission (SCr-H1). Non-steady-state SCr was defined as exceeding the Reference Change Value (RCV), with 15% decrease or 18% increase between successive SCr measurements. Exceeding the RCV was deemed as a significant change.Of visits where SCr-BL and SCr-ED were measured , 28.0% showed significant change in SCr. Of 17,928 visits admitted to the hospital with a SCr-H1 after SCr-ED, 27,7% showed significant change. More than half (55%) of the patients with SCr values available at all three timepoints  showed at least one significant change in SCr over time.One third of ED visits preceded and/or followed by creatinine measurement show non-stable serum creatinine concentration. At the ED automatically calculated eGFR should therefore be interpreted with great caution when assessing kidney function. Assessment of kidney function plays a crucial role in the evaluation and treatment of patients. A change in kidney function can point to renal disease, which is associated with an increase in morbidity and mortality , 2. TimeRenal function is most often quantified as the estimated glomerular filtration rate (eGFR), calculated by the CKD-EPI formula using serum creatinine (SCr), age, gender, and race . The CKDDosing of renally cleared drugs is often based on KDIGO CKD-categories using a measure of eGFR such as the CKD-EPI. When SCr is not in steady-state, drug dosing based on the CKD-EPI may result in potential toxicity or underdosing. Indeed, up to 24% of admitted patients with AKI experience some form of adverse event caused by inadequate drug dosing .In this study we aimed to assess the incidence of non-steady-state SCr concentrations at the ED and therefore situations where the CKD-EPI is potentially unreliable. We hypothesized that a substantial number of patients who visit the emergency department an in whom a serum creatinine concentration is assessed have a serum creatinine concentration that is not in steady-state.We performed a single centre retrospective analysis, using data from the University Medical Centre (UMC) Utrecht, Utrecht, the Netherlands. We evaluated all ED visits between 2012 and 2019 from patients aged over 18 years. Data were extracted from the Utrecht Patient Oriented Database (UPOD) . In brieBeckman Coulter, Brea, CA, USA). For each SCr an eGFR was computed using the CKD-EPI formula [For each ED visit we extracted patient age, sex and hospitalization information. Additionally, all SCr measurements were extracted 365 days prior and up to 24 hours after each ED visit. SCr was measured by enzymatic colorimetric assay ( formula . Chronic formula .We defined the following three SCr measurements: baseline SCr measurement as the most recent SCr measurement within a year before ED presentation (SCr-BL), SCr-ED as the measurement at ED presentation, and a subsequent SCr measurement during hospitalization (SCr-H1). Since very short time-intervals (e.g. 30 minutes) may obscure significant fluctuations in SCr, we defined SCr-H1 as the first measurement closest to 12 hours and at least 6 hours with a maximum of 24 hours after the SCr-ED measurement.a) and within-subject biological coefficient of variation (CVi). Since SCr does not follow a normal distribution due to the underlying first-order elimination, we calculated the RCV using the log-method: i = 5.95% and CVa = 1%) resulting in a significant increase of 18% and a significant decrease of 15% [Significant fluctuation in SCr was defined as exceeding the Reference Change Value (RCV). RCV represents the smallest difference between sequential laboratory results representing a true change in the patient and can be calculated using the analytical coefficient of variation , we also assessed the change in CKD-EPI categories between baseline measurement and ED measurement as well as baseline and the subsequent measurement during admission [Since drug dosing is often based on CKD-EPI categories .Risk of non-steady-state SCr was quantified with logistic regression. 95% confidence intervals for the absolute change in creatinine over time were calculated with smoothed quantile regression. All statistics and pre-processing were performed using the R environment (3.6.1). P-values below 0.05 were considered significant.Between 2012 and 2019 there were 120,652 visits from 69,579 unique patients who visited the ED . Of all Percentages are based on the total number of visits. ED discipline was defined as the first discipline the patient visited during visit.When SCr-ED was compared to SCr-BL, 8,794 visits (18.5%) showed a significant increase and 5,378 (11.3%) showed a significant decrease SCr . The medOf the patients with both a SCr-ED and a SCr-H1, a significant increase was seen in 1,304 (7.3%) and a significant decrease was seen in 3,839 subjects (21.4%) . The medNext, we compared the consistency of SCr in visits with all three measurements available . After a significant rise in SCr between BL and ED , 4.4% continued to rise significantly, 58.7% stabilised, and 36.9% had a significant decrease in SCr . After aWe compared the incidence for non-steady-state SCr between different medical specialties and CKD-stages. Visits with CKD stage 3a or worse were at a higher risk of non-steady-state SCr between SCr-BL and SCr-ED p<0.001; . SimilarNext, we compared the incidence of a non-steady-state creatinine between different medical specialties at the ED, as one might hypothesize that this phenomenon preferentially occurs in certain specialties. Although the percentage of non-steady state creatinine concentrations differed between the different specialties  Tables, Reliable estimation of the GFR at the ED is the cornerstone of assessing renal function and thereby essential for correct dosing of drugs that are renally excreted. However, commonly used renal function formulas  require SCr in steady-state to provide a reliable estimate of the GFR. We found that a third of all the SCr measured at our ED were not in steady-state and that the CKD-EPI may therefore not reflect the underlying renal function. Faulty GFR estimates and CKD staging will affect clinical decision making and drug dosing regimens. Interestingly there appeared to be an inverse correlation between the incidence of non-steady state creatinine concentration and elapsed time since last creatinine concentration measurement before the ED measurement. We found a similar high incidence of non-steady-state SCr across all different specialities.The incidence of non-steady-state SCr and the reliability of the CKD-EPI at the ED has not been widely studied. Previous reports have estimated the incidence of AKI in the general ED-population between 3% and 25%, depending on the definition and the population , 17. OneThe high incidence of SCr not in steady-state in the ED not only has consequences for the interpretation of the CKD-EPI as a measure of kidney function per se, but also for dosing of drugs with a significant renal clearance, since this is often guided by CKD categories indexed by the eGFR. The CKD-EPI based eGFR calculated during ED visit and subsequent admission results in frequently changing CKD categories over time . Moreover, an increase or decrease in CKD-EPI categories from baseline to ED was not associated with a subsequent increase or decrease in CDK-EPI categories from ED to H1. Although the changing CKD categories do reflect changes in underlying renal function, they do not adequately reflect the actual GFR and should therefore be used with caution for dosing of drugs with significant renal clearance.Most formulas that estimate glomerular filtration rate assume a stabilized serum creatinine concentration, and therefore only require the input of one serum creatinine concentration value , 20. PerThere are other instances where serum creatinine based renal function formulas may be inaccurate. These are, amongst others, situations that influence the production or excretion of creatinine independent of GFR, such as aberrant diet, pregnancy, skeletal muscle disease and drugs that influence tubular secretion of creatinine. This further stresses the limitation single serum creatinine concentration based renal function formulas to estimate renal function at the ED. It is of note that cystatin C based renal function formulas have been proposed to be less dependent on muscle mass and diet. However, current cystatin c based renal function formulas also require steady state serum concentrations of cystatin C to estimate renal function from a single serum cystatin C concentration.Strengths of this study are that we used a large dataset with a well-documented and unselected population. This allowed us to study the true incidence of non-steady-state SCr at the ED of our tertiary care hospital over different medical specialities and CKD stages. The detailed time annotation allowed us to not only study non-steady-state SCr between baseline and the ED measurement but also the subsequent measurement within 24h after admission. Furthermore, the use of a relational database such as UPOD ensures maximum completeness and integrity of the data, since it continuously stores laboratory and clinical data for every individual ED visit. This allowed us to perform our analyses on routine care data that is a valid representation how the CKD-EPI formula is used in clinical practice.This study has some drawbacks. This retrospective study only included ED patients in whom creatinine concentrations were determined, which introduced selection. Although this might lead to overestimation of non-steady state creatinine concentrations at the ED population as a whole, it does reflect the incidence of non-steady state creatinine concentration in the ED subpopulation where renal function estimation is deemed appropriate by the treating physician. Another drawback of this retrospective cohort study is the lack of invasive GFR measurements to assess actual GFR. Although currently no validated formula is available to estimate underlying renal function in patients with a non-steady state serum creatinine concentration at the ED, the simple notion that an increasing serum creatinine concentration causes the CKD-EPI to underestimate underlying renal function (and vice versa) is important and may be an incentive to better estimate renal function with timed urine collections. Finally, the current study was neither designed to show any adverse clinical consequences of the faulty GFR estimates nor to quantify potential benefits of improved GFR estimates. However, the abovementioned high percentage of adverse drug reaction due to inadequate dosing in patients suffering from AKI, suggests room for improvement.In conclusion, a third of the patients who visit the ED have non-steady-state SCr. Physicians should be aware of this when using the automatically provided CKD-EPI at the ED and should interpret the reported eGFR with great caution. Future studies should elucidate whether a more tailored GFR estimate (e.g. by using dynamic formulas or timed urine collections) improve drug dosing and/or clinical outcome.S1 TablePercentages are based on the total number of visits per sub-cohort. ED discipline was defined as the first discipline the patient visited during visit. ICU admission was defined as having at least one admission to the ICU during hospital stay.(DOCX)Click here for additional data file.S2 Table(DOCX)Click here for additional data file.S3 Table(DOCX)Click here for additional data file.S4 Table(DOCX)Click here for additional data file.S5 Table(DOCX)Click here for additional data file.S6 Table*: p-value < 0.001.(DOCX)Click here for additional data file.S7 Table*: p-value < 0.001.(DOCX)Click here for additional data file.S1 FigPercentages computed from the total number of ED visits.(TIFF)Click here for additional data file.S2 FigPatients are grouped based on the time to last creatinine measurement before emergency department (ED) visit.(TIFF)Click here for additional data file.


Information is lacking regarding long-term survival and predictive factors for mortality in patients with acute hypoxemic respiratory failure due to coronavirus disease 2019 (COVID-19) and undergoing invasive mechanical ventilation. We aimed to estimate 180-day mortality of patients with COVID-19 requiring invasive ventilation, and to develop a predictive model for long-term mortality.Retrospective, multicentre, national cohort study between March 8 and April 30, 2020 in 16 intensive care units (ICU) in Spain. Participants were consecutive adults who received invasive mechanical ventilation for COVID-19. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection detected in positive testing of a nasopharyngeal sample and confirmed by real time reverse-transcriptase polymerase chain reaction (rt-PCR). The primary outcomes was 180-day survival after hospital admission. Secondary outcomes were length of ICU and hospital stay, and ICU and in-hospital mortality. A predictive model was developed to estimate the probability of 180-day mortality.868 patients were included . Severity at ICU admission, estimated by SAPS3, was 56 points [IQR 50–63]. Prior to intubation, 26% received some type of noninvasive respiratory support. The unadjusted overall 180-day survival rates was 59% (95% CI 56–62%). The predictive factors measured during ICU stay, and associated with 180-day mortality were: age [Odds Ratio [OR] per 1-year increase 1.051, 95% CI 1.033–1.068)), SAPS3 , diabetes , neutrophils to lymphocytes ratio , failed attempt of noninvasive positive pressure ventilation prior to orotracheal intubation (OR 1.878 (95% CI 1.124–3.140), use of selective digestive decontamination strategy during ICU stay (OR 0.590 (95% CI 0.358–0.972) and administration of low dosage of corticosteroids (methylprednisolone 1 mg/kg) (OR 2.042 (95% CI 1.205–3.460).The long-term survival of mechanically ventilated patients with severe COVID-19 reaches more than 50% and may help to provide individualized risk stratification and potential treatments.Trial registration: ClinicalTrials.gov Identifier: NCT04379258. Registered 10 April 2020 (retrospectively registered)The online version contains supplementary material available at 10.1186/s13613-021-00929-y. The coronavirus disease 2019 (COVID-19) pandemic is one of the most serious health crises in recent decades , 4.Currently available information about critically ill adult patients is heterogeneous because of the case-mix of patients, and in-hospital mortality rates differ between countries –9. SpeciWe conducted a multicenter cohort study to analyze the long-term mortality of patients who required invasive mechanical ventilation for severe COVID-19 pneumonia, and determine the impact of predictive variables measured during ICU stay for long-term mortality.This observational cohort study was conducted in 16 surgical and medical ICU at 12 university hospitals in Madrid and Barcelona, the Spanish cities most affected by COVID-19 (a complete list of participating sites is provided in the Supplement). We included all patients who were admitted to the participating ICUs between March 8, 2020 and April 30, 2020, and who required invasive mechanical ventilation for acute hypoxemic respiratory failure secondary to SARS-CoV-2 pneumonia. The diagnosis was confirmed by a positive result of real-time reverse-transcriptase polymerase chain reaction (RT-PCR) testing of a nasopharyngeal swab sample or from a lower respiratory tract sample . SARS-CoVariables recorded were: age, sex, height, weight, severity at admission estimated by the Simplified Acute Physiology Score (SAPS3) [which ranges from 16 points (low severity) to 226 points (high severity)], comorbidities, (previous medication use), mode of respiratory support  or BiPAP (Bi-Level Positive Airway Pressure)), use of compassionate medication  before admission to ICU, length of hospital stay prior to ICU admission, date of intubation, ventilatory settings within the first week of mechanical ventilation, daily arterial blood gases, concentrations of plasma/serum biomarkers drawn within 7 days of ICU admission, including high-sensitivity C-reactive protein, D-dimer, ferritin, high-sensitivity troponin, procalcitonin, and IL-6, use of adjuvant therapies for acute respiratory failure , vasopressor agents, renal replacement therapy, antibacterial agents, antiviral agents, and other immunomodulatory agents, complications, and organ failure during the ICU stay.Patients were followed-up until 180 days after hospital admission. Patients who died were censored at the date of death for the time-to-discharge analysis.Independent on-site monitoring was performed at each participating center in coordination with the main investigators who verified all data.All data were monitored and reviewed by four external investigators  to detect erroneous and missing data.The study was approved by the institutional ethics board at each participating site. The requirement for informed consent from individual patients was waived, because the study design was considered minimal-risk research using data collected for routine clinical practice during an ongoing public health emergency.NCT04379258. We followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement guidelines for observational cohort studies [The study was registered in ClinicalTrials.gov Identifier:  studies .Following the approval of the ethics committee at each participating center, patients were collected retrospectively to allow rapid data collection and over 180 days of prospective follow-up to analyze clinical outcomes .The main outcome was mortality at 180 days. Secondary outcomes were duration of mechanical ventilation, duration of ICU and in-hospital stay, reason for death and destiny at hospital discharge.2 to FiO2 ratio, D-dimer, ventilatory ratio [Variables included in the predictive model were as follows: age, sex, comorbidities , and the following pre-admission medications: angiotensin-converting enzyme inhibitors, angiotensin receptor blockers and chronic steroids. We also included in the model non-invasive respiratory support before orotracheal intubation, time from hospital admission until intubation, SAPS3, relevant variables determined within the first 48 h of admission to the ICU  procedure . Incomplp < 0.05.Mortality outcomes were analyzed using mixed-effects logistic regression in the imputed data sets. The analysis was fitted with a random effect in which the patients were nested in ICUs to characterize ICU-level variation and to estimate center-specific rates of ICU-mortality. The fractional polynomial method was used to explore the behavior of continuous variables. We applied stepwise selection with backward elimination of predictors from the full model with c-statistic: for a binary outcome, c is identical to the area under the receiver operating curve (AUROC). Calibration was evaluated studying the calibration slope and calibration-in-the-large (CITL). This approach indicates the difference between the observed prevalence of death and the predicted mean probability. In a perfect model, the CITL should be equal to zero, but our CITL value was small and the confidence interval contained 0.The final model was then validated by bootstrapping. Using this procedure we sampled 100 samples for each imputed data set with replacement. Discrimination of the model was evaluated using the The calibration slope tells us if the model coefficients are underfitted (slope > 1) or overfitted (slope < 1). In our case, the slope was below 1, so it was insufficient to obtain the data from our model. However, this is not entirely negative, because as a predictive model, we want the model to be able to explain future data from other patients and units, not just our data. Furthermore, 1 is included in the confidence interval, so we can consider it to be a good model in terms of calibration. .Subsequently, coefficients were used to generate a nomogram to predict the adjusted probability of ICU mortality individually.To account for differences in patient-level characteristics and illness severity between ICUs, we calculated the median odds ratio (MOR) .Finally, in a sensitivity analysis for the multilevel model, further adjustments were made for the number of ICU beds at each hospital before the COVID-19 pandemic .2/FiO2 categorized according to the acute respiratory distress syndrome (ARDS) Berlin definition [The 180-day survival outcomes were calculated using a Kaplan–Meier survival plot in an overall cohort and by predefined subgroups .p < 0.05.The differences between survival curves were evaluated by log-rank test. To identify the optimal cut-point value in ROC analysis we used the Youden index approach. Statistical significance was considered at Analyses were performed using Stata, version 16.1 (StataCorp LLC).During the study period, 868 of the 1,170 patients who were admitted to the participating ICUs were included in the analysis. A flow chart of study patients is provided in Additional file Severity at admission to the ICU estimated by SAPS3 was a mean 57 points SD, 11 points) . At admission to the ICU, serum biomarkers and ventilatory settings, arterial blood gases, adjuvant therapies within the first week of mechanical ventilation  and , respectively. Within the first 48 h, ventilatory management  was similar in both cohorts   with those with less than 50 patients (N = 9) and varied widely across centers  and 23% (129/553) were transferred to a nursing facility.At the end of ICU stay follow-up . ICU mortality was 38.5% (95% CI 35%–42%).Among patients discharged alive from the ICU admission, the median ICU length of stay was 17 days  and the median hospital length of stay was 38 days .Predictive interpretations compared with 180-day mortality were largely unchanged when restricted to ICU mortality or hospital mortality Table , althougThe results of the mixed-effect analysis  for respiratory management of patients with severe acute respiratory distress is controversial . StudiesThe beneficial effect of the SDD strategy in mechanically ventilated critically ill patients has been widely studied, and meta-analysis based on individual patient data have consistently shown improved patient outcomes with this approach –37.Indeed, the similarity in ICU mortality between our findings and Dutch study  may be eA hematological dysfunction defined as an increased neutrophil to absolute lymphocyte ratio (NLR) was recently described. The NLR has been identified as biomarker of higher in-hospital mortality . AnotherWe did not find that adjunctive therapies such as prone positioning or the use of neuromuscular blocking agents had a beneficial effect on mortality. It is important to highlight that the predictive model described here is based on the first 48 h of mechanical ventilation. One can, therefore, argue that these measures would not have been implemented for long enough to have a positive clinical impact on patients with severe COVID-19. Furthermore, this observational study collected the local clinical practice from centers during the pandemic outbreak. Most of the patients, therefore, received all these measures, thus limiting the possibility to extrapolate conclusions in the absence of adjusted and reliable comparisons.2 44%), suggesting that different populations or different associated treatment effects may play a role. On the other hand, the multivariate model for long-term outcomes  showed that the administration of corticosteroids had a beneficial effect on mortality.According to recent evidence, treatment with systemic corticosteroids is associated with reduced mortality for critically ill patients with COVID-19 . The clicardiac dysfunction secondary to myocarditis that may influence in the prediction for unfavorable outcomes [Finally, we have found that the need for low dosages of vasopressor support during ICU admission is a predictor for short-term mortality, but not for long term. Due to the observational design of the study we cannot verify the target for mean arterial pressure (MAP) or the hemodynamic management in these patients during ICU stay, neither if those patients had a component of outcomes .Our data indicate that 60% of all deaths among ventilated patients occurred in the first 30 days of ICU stay. These deaths were due to refractory hypoxemia and multiorgan failure, and were probably related to the development of progressive, fibrotic lung disease.Although the virus is eradicated in the most severe COVID-19 patients, the cause of lung damage is not. Linked to the inflammatory response, lung fibrosis emerges as a secondary event related to the progression of the pathology and worse outcomes –48.We acknowledge a number of limitations. First, due to the fact that most participating centers rapidly reached ICU saturation at the critical moment of the COVID-19 outbreak, and as intensivists were facing difficult decisions, not all patients admitted to the participating ICUs during the study period were collected. Nevertheless, we calculated a predefined sample size according to the protocol to reach significant power to detect clinical differences in outcomes. Second, it is plausible that differences in clinical outcomes may be explained by variability in clinical practice. Such an increased risk for ICU mortality can be explained by differences in practice between centers . FinallyOverall survival support in mecahnically ventilated patients with severe acute respiratory hypoxemic failure due to COVID-19 was slightly more than 50% at 180 days but this varied considerably between centers. The evolution and management of these patients during the ICU stay may influence long-term outcomes. Among the clinical modifiable factors that were predictors of death, our findings suggest that a failed attempt of NPPV may be associated with worse outcomes. However, the clinical challenge is still to early identify patients who benefit from NPPV and those who will have worse outcomes. Further studies based on personalized medicine are warranted to evaluate functional outcomes of this population and the multiple candidate therapies to detect treatment-responsive subgroups.Additional file 1. Additional figures and tables.


Shareable e-scooters have become popular, but injuries to riders and bystanders have not been well characterized. The goal of this study was to describe e-scooter injuries and estimate the rate of injury per e-scooter trip.Retrospective review of patients presenting to 180 clinics and 2 hospitals in greater Los Angeles between January 1, 2014 and May 14, 2020. Injuries were identified using a natural language processing (NLP) algorithm not previously used to identify injuries, tallied, and described along with required healthcare resources. We combine these tallies with municipal data on scooter use to report a monthly utilization-corrected rate of e-scooter injuries. We searched 36 million clinical notes. Our NLP algorithm correctly classified 92% of notes in the testing set compared with the gold standard of investigator review. In total, we identified 1,354 people injured by e-scooters; 30% were seen in more than one clinical setting , 29% required advanced imaging, 6% required inpatient admission, and 2 died. We estimate 115 injuries per million e-scooter trips were treated in our health system.Our observed e-scooter injury rate is likely an underestimate, but is similar to that previously reported for motorcycles. However, the comparative severity of injuries is unknown. Our methodology may prove useful to study other clinical conditions not identifiable by existing diagnostic systems. In dozens of cities around the world, riders can use a smartphone app to rent an electrically powered stand-up scooter (known as an “e-scooter”) and leave it on the sidewalk at their destination for use by another rider. While some individuals own e-scooters for personal use, most riders rent on a per-mile basis from private operators. The convenience and ubiquity of these personal transporters has led to rapid growth and expansion. As a result, it is estimated that shareable e-scooters may ultimately capture 8–15% of all trips shorter than 5 miles worldwide [Table 2 in results). No study to date has characterized medical care provided for injuries in a full healthcare system, including in the outpatient setting. Research in this area is hampered by lack of specific diagnosis codes allowing investigators to quickly identify e-scooter injuries. Consequently, the scientific evidence on how much risk e-scooters pose to riders and non-riders remains inadequate.Injuries related to e-scooters were initially largely documented in media reports and led to regulatory reform in some jurisdictions based on limited scientific data on the frequency and types of associated injuries . A previTable 2), allowing for an assessment of trends over time (including during the ongoing COVID-19 pandemic). This is also the first report, to our knowledge, of downstream related healthcare utilization after patients initially seek care. Given the size of our health system and the larger corpus of detailed clinical data available compared with prior studies, as well as the absence of existing diagnosis codes for injuries resulting from e-scooter use, we applied and tested a natural language processing (NLP) technique to review electronic medical records across millions of visits, a technique not previously used in this area. Furthermore, by merging our injury findings with data reported by e-scooter companies to local municipalities, we also provide an estimate of injury rates on a per trip basis.This study provides the first description of outpatient clinic visits related to e-scooters, in addition to ED and hospital encounters, within a large metropolitan area with widespread e-scooter use. We cover a period five-fold longer than any prior work  Health. UCLA Health includes an extensive primary care network in the Southern California region providing more than 10 million clinical encounters each year at over 180 locations. Our study population included all patients 10 to 90 years old (in order to exclude patients unlikely to use e-scooters) who had an encounter at an outpatient clinic, ED, or hospital between January 1, 2014, and May 14, 2020. Encounters occurred in a variety of settings, including primary care, all medical specialties, physical therapy, six urgent care centers, and two hospitals with affiliated EDs . Potential cases were identified from the electronic medical record system using an NLP search of all clinical notes and then confirmed by investigator medical record abstraction.S1 Table in S1 File). This includes a spectrum encompassing major potentially life-threatening traumatic injuries transported by emergency medical services and minor musculoskeletal or skin and soft tissue injuries. Patients involved in e-scooter injuries were further classified as either a rider  or a non-rider . Cases were further classified based on contextual information in the clinical note as either confirmed e-scooter injury  or possible e-scooter injury .An e-scooter injury was defined as any type of injury attributed in medical records to an electrically powered scooter that led the patient to seek medical care . Cases in our prior study had been identified through a search of ED electronic medical record notes from September 1, 2017 to August 31, 2018 using a regular expression to search for e-scooter keywords, namely the word “scooter” (including “e-scooter”) and two proprietary eponyms . The resulting records, which had all been previously examined in our prior study, were again reviewed and abstracted and yielded 112 confirmed non-cases of e-scooter injury , and 249 confirmed cases of e-scooter injuries (the same number reported in our prior study). These formed the core of our initial training data used for NLP model development.ED visit notes from January 1, 2014 to December 31, 2019  were used for training the NLP model . NLP model 1 added notes matching the term “scooter” in any form, including “e-scooter.” NLP model 2 added notes that included brand names of e-scooter operators  and common misspellings (“Byrd” and “Lyme”). Finally, to optimize and balance the training data set with negatives, NLP model 3  was supplemented with random ED clinician notes for admitted patients that lacked any keywords. All notes used for NLP training and testing data, including negatives, were manually reviewed and verified. A total of 2649 labeled clinical notes, consisting of 1036 confirmed positive e-scooter injuries and 1613 confirmed negatives, as confirmed by manual review, comprised the training and testing data used to generate our final NLP model.Fig 1) [At each stage, training data was randomly divided into 70% training and 30% testing subsets. All text in these notes underwent standard NLP pre-processing techniques  and were then used to train a binary classifier to identify scooter-related injury in clinical records. We used an ensemble random multi-model deep learning (RMDL) technique  . NLP modFig 1) , 10. TheFig 2), which included all outpatient visits from January 1, 2014 to May 14, 2020, and ED visits from January 1, 2020 to May 14, 2020 . After exclusion of notes from patients under 10 years of age or over 90, the final NLP model was applied to 125 ED notes and 13,489 outpatient notes that contained the keyword “scooter”. An NLP predicted positive was defined as a note with an NLP-predicted probability of e-scooter injury of 90% or greater, while all other notes were defined as NLP-predicted negatives . All predicted positives were manually reviewed and abstracted by one of the investigators , allowing for exclusion of notes that did not represent e-scooter injuries and tallying false positives from our model (visits not clearly attributable to an e-scooter injury were classed as non-injuries when there was disagreement or uncertainty among investigators). While all NLP-predicted negative notes from the ED set were reviewed, a random 10% sample of NLP-predicted negative notes were reviewed from the outpatient set . This allowed identification of false negatives and estimation of test characteristics against the gold standard of manual review, but false negatives were not included in injury totals.The final NLP model was applied to the testing set ; resources required to evaluate and treat an injury, including clinical visits ; procedures ; imaging ; and physical or occupational therapy care. Care for each distinct patient was analyzed as a unit, but evidence of multiple instances of injury in the same patient  was noted. Correspondingly, our final injury totals are reported at the patient level, while preliminary reviews to build NLP training data and analysis of NLP diagnostic performance took place at the note level. Finally, year and month of injury was identified based on the recorded index encounter date.Information on shareable e-scooter use in the community was obtained from the city governments of Santa Monica  and Los Summary statistics and two-sided hypothesis testing employed chi-squared statistics for categorical data, ANOVA for normally distributed data, and Kruskal-Wallis for nonparametric data, with p-values less than 0.05 considered statistically significant, and all confidence intervals computed at the 95% level. SAS 9.4 and Stata 13.1 software were used for all statistical analyses. The UCLA institutional review board approved this study with waiver of informed patient consent (IRB#18-001294-AM-00004). In accordance with the institutional research policies, a small number of patients who requested not to be included in any research were excluded. The study was conducted using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guidelines .S1 Fig in S1 File). In total, approximately 4 hours of computational time on a standard laptop computer were required, in addition to approximately 1 hour of “wall clock time” for the medical records database to perform a full keyword search. The ED notes from January 1, 2014 to December 31, 2019 were used for a three-stage training and testing process for our NLP algorithm, yielding 1,036 confirmed e-scooter injury notes and 1,613 confirmed negatives after chart review by the investigators .We searched more than 36 million individual clinical notes during the study period to identify e-scooter related injuries .The final NLP algorithm was then tested on remaining ED notes  and the outpatient notes from the entire study period . After excluding patients aged less than 10 or greater than 90, and excluding notes without the keyword “scooter”, we applied the final NLP algorithm to the remaining 90,824 notes to identify those with a 90% or greater predicted probability of an e-scooter injury. Upon review of all predicted positive notes by investigators, 506 of 1,029 outpatient notes (49%) and 43 of 47 ED notes (91%) were confirmed e-scooter injuries (see S2 Table in S1 File and confusion matrix in S3 Table in S1 File).E-scooter injuries were noted in 21 of 78 (27%) and 50 of 1246 (4%) of the NLP predicted negative ED and outpatient notes, respectively. The final NLP algorithm had an accuracy of 92%, meaning that our NLP algorithm correctly classified 92% of notes in the testing set with the keyword “scooter” as predictive of e-scooter injury or not. Our algorithm showed greater specificity than sensitivity, which was more pronounced for outpatient notes, which had a lower prevalence of e-scooter injury than ED notes. Overall, a positive likelihood ratio of 12.2 was noted . Of note, while the NLP identified clinical notes predictive of e-scooter injury, data in Table 1 are presented at the patient level.Injured riders were notably younger (P < .01), had more upper extremity involvement (P = 0.01), and received more minor procedures such as splinting or wound care (P = 0.01) compared to injured non-riders. Overall, 39% of patients received care for injuries sustained in more than one body area, 30% were seen in more than one clinical setting for the injury . General X-ray imaging was obtained in 73%, with advanced imaging  in 29% and major procedures (requiring sedation or anesthesia) performed in 16% of patients. An inpatient admission was noted for 76 patients (6%), of whom 22 required a critical care unit admission. Two e-scooter riders died as a result of trauma after being hit by motor vehicles. Overall, 33% of patients required substantial resource use for their injuries .S5 Table in S1 File). After introduction of shareable e-scooter operators in our region, e-scooter injuries increased to 595 and 672 in 2018 and 2019, respectively. E-scooter use showed marked seasonal variation . During the study period when e-scooter usage data were available for our full catchment area, e-scooter injuries occurred at a mean rate of 54.9 per month, over a mean of 477,209 recorded trips per month, resulting in an overall injury rate of 115 injuries per million e-scooter trips .Prior to the widespread introduction of shareable e-scooters in 2018, there were at most 13 e-scooter injuries per year . Although some existing national database studies have identified similarly large numbers of potentially injured patients, their estimates have varied widely amongst each other, even when using the same data sources, and they have not estimated a utilization-corrected injury rate. In any case, our estimate is substantially higher than prior national estimates of 104 injuries per million motorcycle trips, 15 injuries per million bicycle trips, 8 injuries per million passenger car trips, and 2 injuries per million walking trips [By combining multiple health system and public safety data sources, we estimate a utilization-corrected e-scooter injury rate of 115 injuries per million e-scooter trips in our region; this information has heretofore been limited in the existing literature, illustrating the importance of data-sharing. Our estimate of 115 injuries per million trips is of the same order as the limited existing regional studies, but draws from an order of magnitude more injuries and trips than these studies . Even if, as we advocate, consistent terminology and diagnostic codes for e-scooter injuries are established, our NLP-based approach may be useful for identifying other novel clinical presentations for which diagnosis codes are unavailable or inconsistently used but where large amounts of unstructured electronic data are available. We chose to combine current state-of-the-art supervised learning techniques in order to maximize accuracy and minimize the amount of training data required . These techniques are well established, and the chief novelty of this study is its clinical application and the consequent results.Our study has a number of limitations. First, the e-scooter injury rate we report may be conservative as we do not capture injuries treated at other health systems in our area, nor injuries that may never present to care but nonetheless cause temporary or permanent disability, and we did not include 138 probable e-scooter injuries and roughly 500 injuries missed by our NLP algorithm . Since our study was retrospective in nature, we did not have standardized data collection, and this limits available clinical information. Reliable assessments of substance use, helmet utilization, and the exact geographic location of injuries would allow for further insights. Finally, some e-scooter injuries may have resulted from individually owned e-scooters rather than devices owned by private operators.Our study also has a number of unique strengths. Our NLP methods greatly reduced the burden of manual review of clinical notes; for example, 506 injuries were identified from review of 1,029 NLP predicted positive outpatient notes, whereas manual review of around 12,276 outpatient notes would likely have been required using only keyword search to identify the same number of injuries . In addition, whereas previous reports have described only ED visits related to e-scooter injuries, this is the first study to include data on outpatient clinic visits, thus including the full spectrum of care. This is also the first study to provide data on cumulative downstream related healthcare utilization; our finding that about one in three patients received care in multiple health care settings after their injury highlights a larger impact of these injuries than noted in previous reports. We also provide information on trends over time, including during the Covid-19 pandemic, and utilization corrected injury rate per million e-scooter trips.E-scooters are associated with injury rates more akin to motorcycles than pedal-driven bicycles. We urge caution about the use of e-scooters and encourage further research into public education, urban planning, and municipal regulation efforts to curb e-scooter injuries. The NLP-based algorithms used to search millions of electronic medical records may increasingly provide a method for rapid identification and assessment of other novel health conditions that do not have established diagnosis codes and tracking systems, which may include infectious diseases as well as traumatic injuries.S1 File(DOCX)Click here for additional data file.