Osteoporotic Fractures and Vertebral Body Reshaping in Children With Glucocorticoid-treated Rheumatic Disorders.

Abstract

Osteoporotic fractures are an important cause of morbidity in children with glucocorticoid-treated rheumatic disorders. This work aims to evaluate the incidence and predictors of osteoporotic fractures and potential for recovery over six years following glucocorticoid (GC) initiation in children with rheumatic disorders. Children with GC-treated rheumatic disorders were evaluated through a prospective inception cohort study led by the Canadian STeroid-induced Osteoporosis in the Pediatric Population (STOPP) Consortium. Clinical outcomes included lumbar spine bone mineral density (LS BMD), vertebral fractures (VF), non-VF, and vertebral body reshaping. A total of 136 children with GC-treated rheumatic disorders were enrolled (mean age 9.9 years, SD 4.4). The 6-year cumulative fracture incidence was 16.3% for VF, and 10.1% for non-VF. GC exposure was highest in the first 6 months, and 24 of 38 VF (63%) occurred in the first 2 years. Following VF, 16 of 19 children (84%) had complete vertebral body reshaping. Increases in disease activity and body mass index z scores in the first year and declines in LS BMD z scores in the first 6 months predicted incident VF over the 6 years, while higher average daily GC doses predicted both incident VF and non-VF. LS BMD z scores were lowest at 6 months (mean -0.9, SD 1.2) and remained low by 6 years even when adjusted for height z scores (-0.6, SD 0.9). VF occurred early and were more common than non-VF in children with GC-treated rheumatic disorders. Eighty-four percent of children with VF underwent complete vertebral body reshaping, whereas vertebral deformity persisted in the remainder of children. On average, LS BMD z scores remained low at 6 years, consistent with incomplete recovery.