Bone health and body composition in paediatric patients with idiopathic nephrotic syndrome managed with glucocorticoids

Introduction: Prolonged administration of glucocorticoids (GCs) is known to have deleterious effects on growth and bone integrity. This study aimed to assess the effects of GC therapy on bone health and body composition in South African children with primary nephrotic syndrome (NS). Methods: A retrospective review was performed of idiopathic NS in patients attending the Paediatric Renal Unit at Chris Hani Baragwanath Academic Hospital (CHBAH) between 1 January 2010 and 31 December 2019. Demographics, dual-energy X-ray absorptiometry (DXA) scans, biochemistry results and treatment history were analysed. Results: NS was diagnosed in 346 patients; 145 met inclusion criteria. Histology showed 90 (62.1%) minimal change NS (MCNS). One hundred and twenty-four (85.5%) had steroid-sensitive NS and 21 (14.5%) demonstrated steroid resistance. Sixty-two (42.7%) had at least one relapse with a median (IQR) time to relapse of 356 (179, 453) days. Thirty-three (22.8%) patients had DXA scans performed. Lumbar spine bone mineral density (BMD) z-score was –1.10 (–1.70, –0.30) and whole body less head BMD z-score was –0.81 (–1.86, –0.10). Four (12.1%) DXA patients had documented fractures. Ten (6.9%) patients had hypothyroidism treated with thyroxine; they were relatively younger, stunted, had lower albumin, higher cholesterol and lower bone metabolism markers at diagnosis and on last clinic visit. Conclusions: In paediatric patients with NS who had DXA performed, the fracture prevalence was 12.1% with predominantly incidental vertebral fractures despite normal BMD measurements in those receiving GC therapy. We recommend screening these high-risk NS patients on prolonged GC therapy for hypothyroidism, low BMD and vertebral or non-vertebral fractures.