Validation of renal angina index to improve prediction of acute kidney injury in critically Ill children- A prospective observational cohort study

Abstract

Background : Renal angina index (RAI) is a clinical guide that identifies patients at high risk for acute kidney injury (AKI) by integrating baseline, contextual and clinical evidence of renal injury. It may serve well to optimize biomarker utility. Methods : We performed a prospective observational study of 285 critically ill children aged 1 month to 18 years and followed them up for a minimum duration of 7 days to 28 days with daily documentation of fluid overload, creatinine values, need for renal replacement therapy(RRT), total duration of mechanical ventilation and hospital stay. RAI score of 8 or more was considered as fulfillment of renal angina. Results : Incidence rate for a Day 0 RAI of 8 or more was 49.4% and Day-3 AKI was 10.2%. Day-3 AKI rates were higher in patients with an RAI of 8 or more with the area under the curve of RAI for predicting Day-3 and Day-7 AKI of 0.815 and 0.727 respectively. An RAI under 8 had high negative predictive values (96.5%) for Day-3 AKI. RAI outperformed traditional markers of pediatric severity of illness (Pediatric Index of Mortality-II) for prediction of Day-3 AKI. Additionally, the RAI outperformed all Kidney diseases improving global outcomes (KDIGO) stages for prediction of Day-3 AKI. Conclusion : Renal angina index can predict development of subsequent severe AKI. Fulfillment of renal angina was associated with longer hospital stay, higher mortality, longer duration of mechanical ventilation and higher need for renal replacement therapy.