Incidence and determinants of acute kidney injury in patients with nephrotic syndrome

Background: Retrospective studies from developed countries indicate an increasing prevalence of acute kidney injury (AKI) in nephrotic syndrome. Prospective information on incidence and determinants of AKI in nephrotic syndrome from developing countries is limited. Methods: This prospective study enrolled consecutive patients with nephrotic syndrome, 1 month–18 years old, admitted to a single tertiary care center. Patients were evaluated daily for the development of AKI using Kidney Disease Improving Global Outcomes serum creatinine criteria until day 14 or discharge, along with clinical and biochemical information to determine associated risk factors. Estimated glomerular filtration rate (eGFR) was reassessed at 3 months' follow-up. Results: Of 115 patients (72.2% boys) enrolled at median (interquartile range) age 64 (36–111) months, 25 (21.7%) developed AKI. The incidence density of AKI was 3.3 (2.2, 4.8) episodes per 100 person-days. Stage 3 AKI comprised 64% of cases. Steroid-resistant illness, hypoalbuminemia, and low baseline eGFR were independently associated with the occurrence of AKI. AKI recovered completely or partially in 48% and 20% cases, respectively; 20% of patients remained dialysis-dependent and 12% of patients died. Patients with AKI had significantly longer hospital stay, and lower median eGFR at 3-month follow-up, than those without AKI. Conclusions: AKI affects 21.7% of patients admitted with nephrotic syndrome, is predominantly severe, and is associated with adverse outcomes in one-third cases, prolonged hospital stay, and reduced eGFR at discharge and short-term follow-up. Steroid-resistant nephrotic syndrome, hypoalbuminemia, and low eGFR at admission were independently associated with the occurrence of AKI.