Utility of Renal Angina Index as Compared to Kdigo in Critically Ill Children at a Tertiary Care Hospital in a Low Middle-income Country

Objective: To evaluate the diagnostic accuracy of the Renal Angina Index (RAI) compared to Kidney Disease Improving Global Outcomes (KDIGO) criteria for early prediction of severe acute kidney injury (AKI) in critically ill children admitted to a tertiary care hospital in a low-middle-income country. Methods: This cross-sectional study included critically ill children aged 1 month to 18 years admitted to the Pediatric Intensive Care Unit (PICU) at Aga Khan University Hospital, Karachi, from January to July 2021. Patients with chronic kidney disease or transferred after 24 hours were excluded. RAI was calculated within 24 hours of PICU admission, and its performance in predicting severe AKI (KDIGO stage 2 or 3) was compared with clinical outcomes such as need for renal replacement therapy (RRT), PICU length of stay, and mortality. Results: Among 278 patients, 148 (53.2%) were RAI positive. RAI demonstrated a sensitivity of 82% and specificity of 87% for predicting severe AKI, with an area under the ROC curve (AUC) of 0.90. RAI-positive patients had significantly higher requirements for diuretics (41.2% vs. 3.1%), RRT (10.8% vs. 0%), longer PICU stay (6.33 ± 5.28 vs. 3.71 ± 2.83 days), and higher mortality (23.6% vs. 1.5%) compared to RAI-negative patients. A threshold of RAI ≥8 provided the best balance between sensitivity and specificity. Conclusion: The Renal Angina Index is a highly sensitive and specific tool for early prediction of severe AKI and associated poor outcomes in critically ill pediatric patients. Its implementation could significantly enhance AKI detection and management in resource-limited settings, where conventional biomarkers are often inaccessible.