Evaluation of the accuracy of estimated baseline serum creatinine for acute kidney injury diagnosis.
BACKGROUND
Modern epidemiologic studies of acute kidney injury (AKI) have been facilitated by the increasing availability of electronic medical records. However, pre-morbid reference serum creatinine (SCr) data are often unavailable in such records. Investigators substitute estimated baseline SCr with the eGFR 75 approach, instead of using actually measured baseline SCr. Here, we evaluated the accuracy of estimated baseline SCr for AKI diagnosis in the Japanese population.


METHODS
Inpatients and outpatients aged 18-80 years were retrospectively enrolled. AKI was diagnosed according to the Kidney Disease Improving Global Outcomes (KDIGO) criteria, using SCr levels. The non-AKI and AKI groups were selected using the following criteria: increase 1.5 times greater than baseline SCr ("baseline SCr") or increase 0.3 mg/dL greater than baseline SCr in 48 h ("increase in 48 h"). AKI accuracy defined by the estimated reference SCr, the average SCr value of the non-AKI population (eb-GFR-A approach), or the back-calculated SCr from fixed eGFR = 75 mL/min/1.73 m2 (eGFR 75 approach, or, eb-GFR-B approach in this study), was evaluated.


RESULTS
We analyzed data from 131,358 Japanese patients. The number of patients with reference baseline SCr in the non-AKI and AKI patients were 29,834 and 8952, respectively. For AKI patients diagnosed using "baseline SCr", the AKI diagnostic accuracy rates as defined by eb-GFR-A and eb-GFR-B were 63.5 and 57.7%, respectively, while in AKI diagnosed using "increase in 48 h", the AKI diagnostic accuracy rates as defined by eb-GFR-A and eb-GFR-B were 78.7 and 75.1%, respectively. In non-AKI patients, false-positive rates of AKI misdiagnosed via eb-GFR-A and eb-GFR-B were 7.4 and 6.8%, respectively.


CONCLUSIONS
AKI diagnosis using the average SCr value of the general population may yield more accurate results than diagnosis using the eGFR 75 approach when the reference SCr is unavailable.
['Hatakeyama|Yutaka|Y|', 'Horino|Taro|T|http://orcid.org/0000-0003-0695-7981', 'Nagata|Keitaro|K|', 'Kataoka|Hiromi|H|', 'Matsumoto|Tatsuki|T|', 'Terada|Yoshio|Y|', 'Okuhara|Yoshiyasu|Y|']
D058186:Acute Kidney Injury D000293:Adolescent D000328:Adult D000368:Aged D000369:Aged, 80 and over D015415:Biomarkers D003404:Creatinine D016208:Databases, Factual D005260:Female D005919:Glomerular Filtration Rate D006801:Humans D007668:Kidney D008297:Male D008875:Middle Aged D008954:Models, Biological D011237:Predictive Value of Tests D015203:Reproducibility of Results D012189:Retrospective Studies D055815:Young Adult
Acute kidney injury KDIGO Consensus creatinine-based criteria Estimated baseline creatinine-based criteria Medical database