The modified renal angina index and renal outcomes in critically ill patients: a prospective cohort study

Introduction Existing risk prediction tools for acute kidney injury (AKI) have focused on the prediction of AKI occurrence, but few have addressed clinically meaningful outcomes such as the need for dialysis, mortality and kidney recovery. We sought to study the performance of the modified renal angina index (mRAI) for prediction of major adverse kidney events 30 (MAKE30). Methodology This prospective single-centre observational study was conducted in the medical ICUs of a tertiary care hospital in India from March 2023 to July 2024. We included consecutive adult ICU patients with hospital stays ≥48 hours, excluding those with end-stage kidney disease, prior kidney transplantation, or needing dialysis at admission. The mRAI was calculated 24 hours after ICU admission based on condition scores and changes in serum creatinine, as described by Matsuura et al. The primary outcome was MAKE30, a composite of in-hospital mortality, new renal replacement therapy (RRT) initiation, or persistent renal dysfunction by discharge or day 30. The area under the receiver operating curve (AUROC) was used to assess the performance of the mRAI for MAKE30 prediction and compared with other scores. Results Among 750 eligible patients, 326 (43.4%) experienced MAKE30. The mRAI had an AUROC of 0.75 (95% CI: 0.70-0.78) for MAKE30 prediction, which was numerically higher than that of the SEA-MAKE score (AUROC 0.70), SOFA score (AUROC 0.70) and APACHE II score (AUROC 0.68). Conclusion The mRAI demonstrated good discriminative ability for MAKE30 prediction in critically ill patients. While this may be a promising tool to guide clinical decision-making, further research is warranted. Trial registration Clinical Trial Registry Identifier: CTRI/2023/04/051884