Osteoporosis is associated with anti-topoisomerase I positivity and glucocorticoids use in patients with systemic sclerosis.

Objectives: Patients with systemic sclerosis (SSc) are at increased risk for osteoporosis (OP) and associated fragility fractures. This study aimed to identify underlying risk factors for these conditions in patients with SSc.

Methods: This cross-sectional study was based on a large prospective cohort of patients with SSc using retrospectively collected bone health data. OP was defined as the presence of a T-score below -2.5 at the femoral neck or lumbar spine, a previous major osteoporotic fracture, or the prescription of anti-osteoporotic therapy.

Results: A total of 485 patients fulfilling the ACR/EULAR 2013 diagnostic criteria for SSc, followed in the Lille University Hospital, were included in the study. The prevalence of OP was 23%; fragility fractures occurred in 18% of patients. OP was associated with higher age, diffuse cutaneous subset, interstitial lung disease (ILD), anti-topoisomerase I positivity, treatment with glucocorticoids (GC) and DMARDs in univariable analysis. Multivariable analysis indicated that higher age (OR 1.06 [95%CI 1.04-1.08]), anti-topoisomerase I antibody positivity (OR 2.22 [1.18-4.16]) and treatment with GC (OR 4.48 [2.42-8.26]) were significantly and independently associated with OP.

Conclusion: Our study shows that OP risk in patients with SSc is determined by age, disease-related factors such as diffuse cutaneous subset, ILD and anti-topoisomerase I antibody positivity, but also treatment with GC independently of other factors.