Self reported non-vertebral fractures in rheumatoid arthritis and population based controls: incidence and relationship with bone mineral density and clinical variables

OBJECTIVE: To compare the incidence of self reported non-vertebral fractures after RA diagnosis between female patients with RA and control subjects, and to explore possible associations between non-vertebral fractures and bone mineral density (BMD), disease, and demographic factors. METHODS: 249 women (mean age 63.0 years) recruited from a county register of patients with RA and population controls (n = 249) randomly selected after matching for age, sex, and residential area were studied. Data on previous non-vertebral fractures were obtained from a detailed questionnaire, and BMD was measured at the hip and spine. RESULTS: 53 (21.3%) patients with RA had had 67 fractures after RA diagnosis, the corresponding numbers for controls were 50 (20.1%) and 60 (odds ratio (OR) for paired variables for overall fracture history 1.09, 95% CI 0.67 to 1.77). The overall fracture rates per 100 patient-years were 1.62 and 1.45, respectively, but self reported hip fractures were increased in RA (10 v 2, OR 9.0, 95% CI 1.2 to 394.5). Patients with a positive fracture history had longer disease duration, were more likely to have at least one deformed joint, and had lower age and weight adjusted BMD than those with no fracture history. In logistic regression analysis, fracture history was independently related to BMD only. CONCLUSIONS: With the probable exception of hip fractures, non-vertebral fractures do not seem to be a substantial burden in RA. Similar independent relationships between levels of BMD and fracture history were found in patients with RA and in population based controls.