Changes in hand bone mineral density are associated with the level of disease activity in patients with rheumatoid arthritis: Bone mineral density measurements in the best study

Abstract

OBJECTIVE: To determine if metacarpal bone mineral density (mBMD) gain occurs in patients with rheumatoid arthritis (RA). If mBMD loss is driven by inflammation, we expect to find mBMD gain in patients who are in remission. METHODS: mBMD was measured by DXR in consecutive radiographs of 145 patients with RA with either continuous high (HDA, disease activity score (DAS) >2.4), low (LDA, 1.6ò DAS ≤2.4) or continuous clinical remission (CR, DAS <1.6) during a 1 year observation period. Association of mBMD changes with disease activity was investigated with multinomial regression analysis. Next, clinical variables associated with mBMD gain were identified. RESULTS: Mean change in mBMD in CR patients was -0.03%, compared to-3.13% and -2.03% in HDA and LDA patients (overall, p<0.001). Of the patients in CR, 32% had mBMD loss (≤-4.6 mg/cm(2) /year), compared to 62% and 66% of the patients with HDA or LDA, whereas 26% of the patients in CR had mBMD gain (ò4.6 mg/cm(2) /year), compared to 2% of the patients with HDA and 5% of the patients with LDA. Patients in CR had a higher chance of having mBMD gain, compared with LDA and HDA (RR 14.9, 95%CI: 3.0-18.7 and RR 4.7, 95%CI: 1.2-6.3, respectively). Clinical remission, hormone replacement therapy and lower age were significant independent predictors of mBMD gain. CONCLUSION: In RA, mBMD gain occurs primarily in patients in continuous (>=1 year) clinical remission and rarely in patients with continuous high or low disease activity. This suggests that mBMD loss is driven by inflammation. © 2011 by the American College of Rheumatology.