Risk of Vertebral Fracture in Individuals with End-Stage Renal Disease Secondary to Vasculitis.

Background: Glucocorticoids are central to vasculitis treatment but increase vertebral fracture risk. This study assessed whether vasculitis as the cause of ESRD is associated with incident vertebral fracture, controlling for corticosteroid use.

Methods: A retrospective cohort study was conducted from 2006-2019 on adults in the U.S. Renal Data System initiating dialysis between 2006 and 2017, surviving ≥1 year, with continuous Medicare Part D coverage during the first year of dialysis. Primary exposure was vasculitis as the cause of ESRD determined from form Centers for Medicare & Medicaid Services (CMS)-2728, completed by a physician at dialysis initiation. A granulomatosis with polyangiitis (GPA) subgroup had ≥1 International Classification of Diseases (ICD)-9/10 code for GPA in the first dialysis year. One inpatient or two outpatient ICD-9/10 codes within 90 days defined incident vertebral fracture. Clinical covariates were ascertained from form CMS-2728 and ICD-9/10 codes and pharmacy claims over the first dialysis year. Multivariable logistic regression examined the association of ESRD secondary to vasculitis with incident vertebral fracture, and in GPA in a secondary analysis.

Results: Among 633,543 individuals with ESRD, vertebral fracture occurred in 6.18% with and 3.23% without ESRD from vasculitis. After multivariable adjustment including corticosteroid daily dose in the first dialysis year, ESRD secondary to vasculitis was associated with vertebral fracture (relative risk (RR):1.33, 95% confidence interval (CI):1.17-1.52), and similarly in those with GPA (RR:1.47, 95% CI:1.23-1.75).

Conclusions: ESRD from vasculitis, and from GPA specifically, increases vertebral fracture risk among individuals with ESRD after accounting for first dialysis year corticosteroid dose.