Vitamin D Deficiency in Nephrotic Syndrome

Background Vitamin D deficiency is common in children with nephrotic syndrome (NS) due to loss of vitamin D-binding protein and albumin in urine, as well as steroid therapy. Its association with disease activity and relapse remains uncertain. Objective To evaluate vitamin D status and assess its association with remission and relapse over 6 months. Methods This prospective observational study was conducted at a tertiary care center (November 2019–May 2021). Thirty children (1–18 years) with a first episode or relapse of steroid-sensitive NS were enrolled. Clinical parameters and serum 25-hydroxyvitamin D levels were recorded at baseline. Participants were followed for 6 months to document remission time and relapse. Correlation and multivariate logistic regression analyses were performed. Results Vitamin D deficiency (<12 ng/mL) was present in 96.7% of children (mean 6.2 ± 2.1 ng/mL). Serum 25(OH)D showed moderate inverse correlations with 24-h urinary protein (ρ = −0.44, P = 0.025) and a significant association with serum albumin (ρ = −0.47, P = 0.014). Vitamin D levels did not differ between early and late steroid responders (P = 0.637). Eight children relapsed during follow-up. Baseline vitamin D levels were lower in relapsers than in nonrelapsers (P = 0.038). However, vitamin D was not independently associated with relapse after adjustment. Conclusion Vitamin D deficiency is nearly universal in active disease and correlates with disease severity markers, but is not an independent predictor of relapse. Routine screening and correction are important for bone health rather than serving as a prognostic biomarker for relapse.