Incidence and risk factors of acute kidney injury among childhood nephrotic syndrome: a prospective cohort study

Acute kidney injury (AKI) is a known independent risk factor for morbidity/mortality but there is scarcity of robust data on it among childhood nephrotic syndrome (NS). We assessed the incidence of AKI among hospitalized children with NS as well as looked for any significant risk factors. Prospective observational study conducted across two tertiary pediatric hospitals in Eastern India from September 2020 to August 2021. Children aged 1-18 years admitted with NS and without any nephritic features or pre-existing chronic kidney disease (CKD) were included. In 200 admissions (n = 176; 63% female, median age 4 years [IQR: 3-7]), AKI occurred in 36 (18%; 95% CI 13 to 36%). Two children required kidney replacement therapy and one death was recorded. In 27/36 (75%), AKI resolved within 48 h, 4 had persistent AKI, 3 acute kidney disease, and two progressed to CKD. On multivariate regression analysis: fractional excretion of sodium ≤ 0.2% (OR 12.77; 95% CI 3.5-46.4), male gender (OR 6.38; 95% CI 2.76-14.74), underlying infection (OR 5.44; 95% CI 2.4-11.86), nephrotoxic drugs (OR 4.83; 95% CI 2.21-10.54), and albumin ≤ 1.4 g/dl (OR 4.35; 95% CI 1.55-12.8) were associated with AKI. A predictive equation using these five variables on admission had high AUC (0.86) in correctly identifying 17 children who subsequently developed AKI. Conclusion: In a low resource setting, AKI is common among hospitalized children with NS. Larger multi-center prospective studies are needed to refine prediction equations and test its utility in preventing AKI development. What is Known: • Acute Kidney Injury is a known independent risk factor for increased morbidity and mortality. • There are few studies to assess the incidence of Acute kidney injury in hospitalised cases of childhood nephrotic syndrome.. What is New: • This is the largest prospective cohort of children suffering from nephrotic syndrome, in India, proposing a novel algorithm for predicting the risk of AKI among hospitalised cases of childhood nephrotic syndrome.