Changes in bone mineral density over 10 years in patients with early rheumatoid arthritis

Objectives To investigate changes in bone mineral density (BMD) in patients with early rheumatoid arthritis (RA) over a 10-year period. Methods Consecutive patients with early RA (symptom duration <12 months) were followed according to a structured programme and examined with dual-energy X-ray absorptiometry (DXA) at inclusion and after 2, 5 and 10 years. Mean Z-scores over the study period were estimated using mixed linear effect models. Changes in Z-scores between follow-up visits were analysed using paired T-tests. Results At inclusion, 220 patients were examined with DXA. At the femoral neck, the mean Z-score over 10 years was -0.33 (95 % CI -0.57 to -0.08) in men and -0.07 (-0.22 to 0.08) in women. Men had significantly lower BMD at the femoral neck than expected by age at inclusion (intercept Z-score value -0.35; 95 % CI -0.61 to -0.09), whereas there was no such difference in women. At the lumbar spine, the mean Z-score over the study period for men was -0.05 (-0.29 to 0.19) and for women 0.06 (-0.10 to 0.21). In paired comparisons of BMD at different follow-up visits, femoral neck Z-scores for men decreased significantly from inclusion to the 5-year follow-up. After 5 years, no further reduction was seen. Conclusions In this observational study of a limited sample, men with early RA had reduced femoral neck BMD at diagnosis, with a further significant but marginal decline during the first 5 years. Lumbar spine BMD Z-scores were not reduced in men or women with early RA. Data on 10-year follow-up were limited.