Incidence of Vertebral Fractures in Women with Systemic Lupus Erythematosus After 8 Years of Follow-Up

The aim of this study was to evaluate possible associations between potential risk factors and the occurrence of established vertebral fractures (VF) in Mexican patients with systemic lupus erythematosus (SLE). Consecutive patients with SLE were enrolled in a prospective, observational study from 2006 to 2015. Information on potential risk factors, including demographics, clinical data, and bone mineral density (BMD) at the lumbar spine and hip on dual-energy X-ray absorptiometry was collected at baseline and follow-up. Semiquantitative analysis was used to determine incident VF on lateral thoracic and lumbar radiographs, defined as any vertebral body graded normal at baseline and at least mildly deformed (20-25% reduction or more in any vertebral height) during follow-up. Differences in baseline characteristics were assessed in patients with and without new radiographic VF. Of 110 SLE patients included, with a median follow-up of 8 (IQR 8-9) years, 22 (20%) had radiographic VF at baseline; 35 (32%) patients had a new VF. The annual incidence rate of new morphometric VF was 3.5 (95% CI 2.4-4.91) per 100 patient/years. Most fractures were mild or moderate and biconcave shaped. Incident VF were significantly associated with baseline BMD at the total hip and longer disease duration. Cumulative glucocorticoid dose, postmenopausal status, and previous prevalent VF were not associated with VF. In this SLE cohort in daily clinical practice, new VF were frequently present in SLE patients, especially those with longer disease duration and low-hip BMD.