Objectives To examine non-vertebral fractures (N-VF) in RA patients, of similar age, disease duration and rheumatoid factor status recruited from three European countries, and their association with bone mineral density (BMD), demographic and disease related associates.
Methods 150 (50 from each country) consecutive female RA patients (ACR 1987 criteria, disease duration > 5 yrs, age 50–70 yrs) visiting the out-patient Department of Rheumatology in the participating centres were included. Data on N-VF occurring after age 25 and after RA diagnosis, demographics and measures of disease activity were collected. Dual energy X-ray absorptiometry (DXA) was used to measure femoral neck and spine L2–4 BMD adjusted for age, weight and height. BMD was expressed in g/cm2. To investigate associations between history of N-VF and disease related variables, we used bi-variate (Students t-test, Pearson Chi square test) and multivariate statistical analyses (logistic regression).
Results A total of 25 patients (Oslo 11, Truro 1 and Amsterdam 13 patients) reported a history of previous N-VF (total number of fractures 34). In the Truro patients BMD (adjusted for age, weight and height) in both spine and hip was higher than in Oslo and Amsterdam patients. A statistical difference between those with and without a previous N-VF was found for the variables (mean (SD)) listed in the Table 1 and for disease duration (22.6 vs. 16.6 yrs, p = 0.01). BMD in the femoral neck but not in the spine was independently associated with a history of a N-VF after adjusting for age, weight, height, disease duration and Larsen score using logistic regression.
Conclusion Our cross sectional findings indicate that BMD is a risk factor for N-VF in female RA patients. Weather this concerns a causal relationship needs confirmation in prospective studies.