Kidney Week

Abstract: FR-OR08

AKI Diagnostic Accuracy and Implications of AKI Baseline Creatinine (ABC) vs. Other Baseline Creatinine Estimating Equations

Session Information

• AKI Prediction and Assessment: Traditional and Novel Tools
  November 03, 2023 | Location: Room 118, Pennsylvania Convention Center
  Abstract Time: 05:33 PM - 05:42 PM

Category: Acute Kidney Injury

• 101 AKI: Epidemiology, Risk Factors, and Prevention

Authors

• Bjornstad, Erica C., The University of Alabama at Birmingham Department of Pediatrics, Birmingham, Alabama, United States

Erica C. Bjornstad, MD, PhD, MPH

• Acharjee, Mithun Kumar, The University of Alabama at Birmingham Department of Biostatistics, Birmingham, Alabama, United States

Mithun Kumar Acharjee,

• Rahman, Akm Fazlur, The University of Alabama at Birmingham Department of Biostatistics, Birmingham, Alabama, United States

Akm Fazlur Rahman,

• Zappitelli, Michael, Toronto Hospital for Sick Children, Toronto, Ontario, Canada

Michael Zappitelli,

• Basu, Rajit K., Ann and Robert H Lurie Children's Hospital of Chicago, Chicago, Illinois, United States

Rajit K. Basu,

• Schwartz, George J., University of Rochester, Rochester, New York, United States

George J. Schwartz,

• Goldstein, Stuart, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States

Stuart Goldstein,

• Braun, Chloe Grace, The University of Alabama at Birmingham Department of Pediatrics, Birmingham, Alabama, United States

Chloe Grace Braun,

• Askenazi, David J., The University of Alabama at Birmingham Department of Pediatrics, Birmingham, Alabama, United States

David J. Askenazi,

Background

Acute kidney injury (AKI) definitions rely on a known baseline creatinine (Cr_b), which is missing in up to 75% of hospitalized children. A new method (ABC equation) for estimating Cr_b was derived from children without kidney disease. We aim to externally validate the ABC method in an international cohort and assess how different Cr_b estimating equations alter AKI epidemiology.

Methods

AWARE is a prospective international study of 4984 critically ill children (age 0-25 years) from 32 PICUs. The validation of the ABC equations uses a subset of this cohort (n=2451) with a known Cr_b which serves as the gold standard, using statistical measures of accuracy and precision. The entire cohort is used for assessing changes in AKI epidemiology for different Cr_b estimating equations (3 ABC equations and 4 common eGFR equations). Univariate statistics determine how different Cr_b equations impact the incidence of AKI and its association with key clinical outcomes including 28-day mortality.

Results

The simplified ABC equation (requiring only age) performed similarly to existing Cr_b equations (e.g., new Schwartz). When an admission hospital creatinine value was available, the ABC equations outperformed all existing equations up to 19% in accuracy and 32% in precision. AKI incidence varied from 2-10% depending on Cr_b definition. Adverse clinical outcomes were rare: 28-day mortality (n=169) was 3.4% and ICU length of stay>=14 days (n=147) was 2.9%. Compared to previous Cr_b equations, ABC equations consistently perform better (or similar) to predict poor clinical outcomes. For example, relative risk (RR) of AKI using the ABC equation for 28-day mortality was 4.5 (95% CI 2.8-7.2); this was 5-29% higher RR than AKI defined by other Cr_b equations.

Conclusion

ABC equations outperform existing Cr_b estimating equations. This international cohort confirms earlier findings that ABC equations are improved methods for estimating Cr_b values. The data suggest ABC equations performed similarly, or perhaps better, in predicting select poor clinical outcomes.