Osteoporosis is a frequent complication of rheumatoid arthritis (RA). We therefore investigated the effect of oral pamidronate therapy as a specific bone-sparing agent in RA.
The study design was a 3-year randomized, double-blind trial of 300 mg oral pamidronate/day compared with placebo in 105 RA patients. Bone mineral density (BMD) measured at 12-month intervals was the primary efficacy parameter.
In 3 years, lumbar spine and forearm BMD increased significantly in the pamidronate-treated group (by 8.4 +/- 6.9% [mean =/- SEMI] [P < 0.00011 and 5.2 =/- 6.5% [P < 0.005], respectively), compared with nonsignificant changes in the placebo-treated patients (increase of 0.6 =/- 5.2% and decrease of 1.2 =/- 5.8%, respectively). Femoral neck BMD increased in the pamidronate-treated group (by 2.6 =/- 8.6%) and decreased significantly in the placebo-treated group (by 4.0=/- 1.3% [P < 0.005]). The changes in BMD with time at all 3 measurement sites were significantly different between the treatment groups (P < 0.0001). Changes in radiographic signs of joint damage and in disease activity were similar in the 2 groups.
The present study provides the first evidence that long-term treatment with an orally administered bisphosphonate overcomes bone loss and increases bone mass when compared with placebo. This finding may have significance with regard to the treatment of patients with RA.