Prediction of Severe Acute Kidney Injury using Renal Angina Index in a Pediatric Intensive Care Unit

Objectives To determine the proportion of children in a pediatric intensive care unit with a positive Day 0 Renal angina index who develop severe acute kidney injury (AKI) on Day 3; and to compare the predictive ability of the index with that of individual markers of renal injury, for the development of severe acute kidney injury. Design Observational study. Setting Pediatric intensive care unit of a tertiary-care hospital. Participants Consecutive children, 1 month to 12 years, admitted in Level 3 pediatric intensive care unit for a minimum of 8 hours, having weight and intake-output records, were eligible. Children known to have chronic kidney disease or already in stage 2/3 acute kidney injury/dialysis were excluded. Procedure Day 0 Renal angina index was calculated from the product of Risk Group score (Pediatric intensive care admission/Ventilation and inotropy) and Renal Injury score (fluid overload over previous 8 hours or the % fall in estimated creatinine clearance from baseline). Renal angina index >= 8 was considered positive. Main outcome measure The proportion of children with positive Day 0 Renal angina index who develop severe AKI (Kidney Disease Improving Global Outcomes (KDIGO) >= Stage 2) on Day 3. Results Of 162 enrolled children (median (IQR) age 10.5 (3,39) months), 86 (53%) had positive Renal angina index. On Day 3, a higher proportion of children with positive index developed severe AKI, compared to negative group (RR 95.5; 95% CI 21.7,420.5; P<.001). Day 0 positive Renal angina index had a sensitivity, specificity, positive predictive value and negative predictive value of 96.9%, 75.5%, 72% and 97.4% respectively, for predicting severe AKI on Day 3. The Receiver Operating Characteristic curve of Day 0 renal angina scores showed AUC of 0.90 (95% CI 0.85, 0.95), better than the AUC obtained from either Day 0 serum creatinine or Day 0 percent fall in estimated creatinine clearance from baseline. Conclusion Day 0 Renal angina index positivity is a promising tool to identify critically ill children with impending severe AKI.