Increased risk of osteoporotic fractures in patients with systemic sclerosis: A nationwide population-based study

Objectives: To identify the incidence rate (IR) and risk factors of osteoporotic fractures (OFs) among systemic sclerosis (SSc) patients. Methods: A cohort study was conducted using the Taiwan National Health Insurance database. Patients with SSc and respective age- and gender-matched controls without SSc were enrolled. The primary endpoint was the first occurrence of OF. The Cox proportional hazard model was used to investigate the risk factor of OFs in the SSc cohort. Results: Among 1712 SSc patients (77.8% female, mean age 50.3 years) with a median follow-up of 5.2 years, 54 patients developed vertebral fractures, 17 patients developed hip fractures, and 7 patients developed radius fractures (IR: 6.99, 2.18 and 0.90 per 1000 person-years, respectively). Compared with the controls, the incidence rate ratios (IRRs) (95% CIs) among SSc patients were 1.78 (1.30 to 2.39, p<0.001) for vertebral fractures and 1.89 (1.05 to 3.22, p=0.026) for hip fractures. The IRRs for overall OFs were 1.74 (1.32 to 2.27, p<0.001) for women and 1.06 (0.33 to 2.66, p=0.856) for men. The SSc patients experienced hip fractures at a younger age (67.2 vs 75.2 years, p=0.005), and had a higher 1-year mortality rate (13% vs 3%, p=0.006) of vertebral fractures than did the controls. Multivariable Cox regression analyses indicated that older age, being female, using daily prednisolone equivalent to >7.5 mg, and bowel dysmotility treated with intravenous metoclopramide are associated with OF. Conclusions: SSc patients had a high IR of vertebral and hip fractures, especially those who were female, older, used a high dose of corticosteroid or experienced bowel dysmotility.