Factors associated with KDIGO stage 3 acute kidney injury in pediatric leptospirosis

Leptospirosis is a significant public health problem, with acute kidney injury (AKI) representing one of its severe complications. However, data on pediatric patients remain limited. To determine clinical characteristics and factors associated with KDIGO Stage 3 AKI in pediatric leptospirosis at Hatyai Hospital. This retrospective study included patients’ diagnosis with leptospirosis, aged 2–15 years, between 2013 and 2023. AKI was classified using Kidney Disease: Improving Global Outcomes (KDIGO) criteria into two groups: group 1 KDIGO stage 3 AKI and group 2 non-stage 3 AKI (stages 1–2 or normal kidney function). Of 155 pediatric leptospirosis, 106 were included in this study. KDIGO stage 3 AKI found 24.5% ( n = 26). Univariable analysis revealed significant factors including lower hematocrit, low platelets, low serum albumin, low serum bicarbonate and the presence of pulmonary hemorrhage. Multivariate analysis showed that serum bicarbonate remained an independently associated with KDIGO stage 3 AKI (adjusted OR = 0.74, 95% CI 0.62–0.91, p = 0.003). Furthermore, the KDIGO stage 3 AKI group had significantly higher rates of kidney replacement therapy, prolonged hospital stays and increased pediatric intensive care unit (PICU) admission. The mortality rate was 0.9%. KDIGO stage 3 AKI occurred in one-fourth of pediatric leptospirosis. Low serum bicarbonate is independently associated with KDIGO stage 3 AKI but requires cautious interpretation, as a reflection of overall disease severity and systemic metabolic acidosis rather than a specific precursor of kidney injury. Early kidney assessment is essential, and further larger-scale studies are warranted to validate these associated markers.