Vitamin d supplementation and bone health in children with nephrotic syndrome: A systematic review and meta-analysis

Abstract

Background: While steroids have been the standard treatment in nephrotic syndrome (NS), they are known to deleteriously affect bone mineralization. Objectives: The objectives were to determine the efficacy and safety of vitamin D supplementation among children with NS on steroid therapy. Methods: We searched databases, scanned reference lists, and contacted trial investigators. Two reviewers collected and graded randomized controlled trials comparing oral vitamin D3 with placebo or no intervention in terms of bone mineral content/density (BMC/BMD), serum markers, and adverse events in pediatric NS. Results: We included 4 trials (164 subjects) with a collectively high risk of performance and/or detection bias. Although the vitamin D group had significantly more positive absolute change-from-baseline BMC than controls (mean difference 1.15; 95% CI 0.07-2-22;I 62%), the two trials were heterogeneous and included data. Moreover, in terms of other outcome measures, we did not find sufficient evidence of benefit from treatment. One study reported significantly improved parathyroid hormone levels but also a higher risk of hypercalciuria with vitamin D use. No nephrocalcinosis was reported. Subgroup analysis of first-episode NS revealed significantly more improved BMD with supplementation. Conclusion: Available evidence was low-quality and insufficient to recommend vitamin D supplementation in pediatric NS, although there may be benefit in first-episode NS. In contrast, vitamin D administration may be associated with hypercalciuria.