Incidence and risk factors of fractures in patients with rheumatoid arthritis: an Asian prospective cohort study

Abstract

Rheumatoid arthritis (RA) patients have high risk for osteoporosis and fracture. We aimed to identify the incidence rate and risk factors of fractures in Asian RA patients. A total of 3557 RA patients in the KORean Observational study Network for Arthritis (KORONA) were included and observed over a mean follow-up of 18 months. A fracture was assessed as total, major, or minor fractures; major fracture was defined as a vertebral or hip fracture, and the other fractures were classified as minor fractures. The standardized incidence ratio (SIR) of fracture in RA patients was calculated compared with general population, and possible risk factors for fractures were explored using multivariable logistic regression analyses. A total of 194 patients with 215 fractures were observed, and the SIR of the total fracture in RA patients was 2.2 [95 % confidence interval (CI) 1.9-2.6]. The SIRs of major and minor fractures were 1.5 (CI 1.1-2.0) and 3.0 (CI 2.5-3.7), respectively. Advanced age [odds ratio (OR) 1.03, CI 1.02-1.05, p < 0.01] and having history of prior fracture (OR 2.17, CI 1.54-3.08, p < 0.01) were risk factors for total fractures. In addition, higher HAQ increased fracture risk (OR 2.02, CI 1.05-3.89, p = 0.04), whereas the use of bisphosphonate showed protective effect for future fractures (OR 0.34, CI 0.14-0.87, p = 0.02) in patients with osteoporosis. RA patients had a 2.2-fold increased risk of fractures as compared with general population. In Asian RA patients, advanced age and history of prior fracture were the most important risk factors for new fractures.