Abstract
Introduction: Classification of acute kidney injury (AKI) requires a premorbid baseline creatinine, often unavailable in studies in acute infection.
Methods: We evaluated commonly used surrogate and imputed baseline creatinine values against a “reference” creatinine measured during follow-up in an adult clinical trial cohort. Known AKI incidence (Kidney Disease: Improving Global Outcomes [KDIGO] criteria) was compared with AKI incidence classified by (1) back-calculation using the Modification of Diet in Renal Disease (MDRD) equation with and without a Chinese ethnicity correction coefficient; (2) back-calculation using the Chronic Kidney Disease–Epidemiology Collaboration (CKD-EPI) equation; (3) assigning glomerular filtration rate (GFR) from age and sex-standardized reference tables; and (4) lowest measured creatinine during admission. Back-calculated distributions were performed using GFRs of 75 and 100 ml/min.
Results: All equations using an assumed GFR of 75 ml/min underestimated AKI incidence by more than 50%. Back-calculation with CKD-EPI and GFR of 100 ml/min most accurately predicted AKI but misclassified all AKI stages and had low levels of agreement with true AKI diagnoses. Back-calculation using MDRD and assumed GFR of 100 ml/min, age and sex-reference GFR values adjusted for good health, and lowest creatinine during admission performed similarly, best predicting AKI incidence (area under the receiver operating characteristic curves [AUC ROCs] of 0.85, 0.87, and 0.85, respectively). MDRD back-calculation using a cohort mean GFR showed low total error (22%) and an AUC ROC of 0.85.
Conclusion: Current methods for estimating baseline creatinine are large sources of potential error in acute infection studies. Preferred alternatives include MDRD equation back-calculation with a population mean GFR, age- and sex-specific GFR values corrected for “good health,” or lowest measured creatinine. Studies using surrogate baseline creatinine values should report specific methodology.
| Original language | English |
|---|---|
| Pages (from-to) | 645-656 |
| Number of pages | 12 |
| Journal | Kidney International Reports |
| Volume | 6 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - Mar 2021 |
Bibliographical note
Funding Information:This work was supported by the Australian National Health and Medical Research Council (grant numbers 1037304 and 1045156; fellowships to NMA [1042072], BEB [1088738], and MJG [1138860]); and Improving Health Outcomes in the Tropical North: A multidisciplinary collaboration “Hot North” (grant 1131932); and the Australian Centre of Research Excellence in Malaria Elimination. The Sabah malaria research program is supported by US National Institutes of Health (R01 AI116472–03). DJC is supported by Australian Government Prestigious International Research Tuition Scholarship (PIRTS) and University Postgraduate Research Scholarship (UPRS). KP is supported by the Michael Smith Foundation for Health Research Health Professional-Investigator Program award and the Mahidol Oxford Tropical Medicine Research Unit.
Funding Information:
TFH has received research funding from AstraZeneca and GlaxoSmithKline. The other authors declared no competing interests.
Funding Information:
The authors acknowledge and thank the participants in this study; clinical and laboratory research staff; the hospital directors, medical and nursing staff at Queen Elizabeth Hospital, Kota Kinabalu, Keningau District Hospital, Ranau District Hospital, and Kota Marudu District Hospital for support and the Director-General, Ministry of Health, Malaysia for permission to publish this manuscript. This work was supported by the Australian National Health and Medical Research Council (grant numbers 1037304 and 1045156; fellowships to NMA [1042072], BEB [1088738], and MJG [1138860]); and Improving Health Outcomes in the Tropical North: A multidisciplinary collaboration ?Hot North? (grant 1131932); and the Australian Centre of Research Excellence in Malaria Elimination. The Sabah malaria research program is supported by US National Institutes of Health (R01 AI116472?03). DJC is supported by Australian Government Prestigious International Research Tuition Scholarship (PIRTS) and University Postgraduate Research Scholarship (UPRS). KP is supported by the Michael Smith Foundation for Health Research Health Professional-Investigator Program award and the Mahidol Oxford Tropical Medicine Research Unit. DJC, BEB, NMA, MJG, TW, AP, and GSR conceived and designed the study and led data collection. DJC, BEB, NMA, MJG, KP, and ZW analyzed the data and interpreted results. DJC, BEB, NMA, MJG, and KP wrote and revised the manuscript. TFH contributed to analysis and revised the manuscript. All authors read and approved the final manuscript.
Publisher Copyright:
© 2021
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
