Association Between Nephrotic Syndrome Status (Active Disease and Remission) and Vitamin D and Calcium Levels in Children

Abstract

Pediatric nephrotic syndrome causes massive proteinuria, resulting in urinary loss of albumin, vitamin D-binding protein, and calcium-binding proteins. These losses may lead to vitamin D deficiency and impaired calcium homeostasis. Evidence regarding the association of active disease and remission with vitamin D and calcium levels among Indonesian children remains limited. This study aimed to examine the association between nephrotic syndrome status (active disease and remission) and vitamin D and calcium levels in children at Adam Malik Hospital, Medan. This analytical observational study used a cross-sectional design and included children aged 1-18 years with active nephrotic syndrome or nephrotic syndrome in remission. Data were obtained from medical records and laboratory measurements of serum 25-hydroxyvitamin D [25(OH)D] and calcium. Univariate analysis was used to describe participant characteristics. Associations between variables were assessed using the chi-square test or Fisher's exact test, with statistical significance set at p < 0.05. A total of 66 patients were analyzed, including 33 with active nephrotic syndrome and 33 in remission. In the active-disease group, 90.9% had vitamin D deficiency and 78.8% had hypocalcemia. Fisher's exact test showed a significant association between nephrotic syndrome status and vitamin D status (p = 0.033). In contrast, nephrotic syndrome status was not significantly associated with calcium status (p = 0.108), although hypocalcemia was more frequent in the active-disease group than in the remission group. Active nephrotic syndrome was significantly associated with vitamin D deficiency but not with serum calcium status. Periodic monitoring of vitamin D levels should be considered as part of the evaluation of children with nephrotic syndrome, particularly during active disease, to prevent complications related to bone and mineral metabolism.