Effect of Vitamin D Supplementation on Albuminuria in Chronic Kidney Disease: A Randomized Controlled Trial

Abstract

Background: Chronic kidney disease (CKD) is a major public health concern worldwide, with a prevalence of 22.5% in Bangladesh. Vitamin D deficiency is common among CKD patients and is associated with increased albuminuria and renal function decline. Vitamin D metabolites may exert reno-protective and anti-proteinuric effects. This study aimed to evaluate the effect of vitamin D supplementation on albuminuria in CKD patients through a randomized clinical trial. Materials and Methods: This single-blind, randomized controlled trial was conducted at the National Institute of Kidney Diseases and Urology, Dhaka, from January 2021 to February 2022. Adult CKD patients (stages 3–5, non-dialysis) with vitamin D deficiency (<30 ng/ml) were randomized to receive weekly oral cholecalciferol 50,000 IU (n=56) or placebo (n=59) for 12 weeks. Primary outcomes were changes in serum 25-hydroxyvitamin D [25(OH)D] and urinary albumin-to-creatinine ratio (uACR). Results: Baseline 25(OH)D levels were lower in the intervention group than controls (14.1 vs. 19.6 ng/ml, p<0.05). After 12 weeks, 25(OH)D increased by 12 ng/ml (85%) in the intervention group versus 0.7 ng/ml (3%) in controls (p<0.05). uACR decreased by 882 mg/g (41%) in the intervention group versus 445 mg/g (22%) in controls (p<0.05). No significant changes were observed in serum calcium, phosphate, or eGFR between groups. Conclusion: Weekly cholecalciferol supplementation significantly improved vitamin D status and reduced albuminuria in CKD patients over 12 weeks.