To determine the effects of low dose methotrexate (MTX) on bone mineral density (BMD) of patients with rheumatoid arthritis (RA).
We examined the relationship between BMD and disease modifying antirheumatic drug (DMARD) use with data from a prospective, randomized, placebo controlled trial assessing the effects of calcium and vitamin D3 supplementation on BMD of patients with RA. Measurements of BMD of the lumbar spine and femoral neck were performed at baseline and at yearly followup visits over 3 years.
Information about DMARD use and BMD was available for 133 patients at baseline, and for 95 patients at Year 3. Lumbar spine and femoral neck BMD of MTX and non-MTX treated patients were similar at the start of the study. At the end of 3 years of followup, there was no significant differences in the change in BMD of the femoral neck and lumbar spine in MTX and non-MTX treated patients, in general. However, patients treated with prednisone > or = 5 mg/day plus MTX had greater loss of BMD in the lumbar spine than patients treated with a similar dose of prednisone without MTX (difference -8.08% over 3 years; p = 0.004).
At the end of 3 years, low dose MTX use was not associated with change in femoral neck or lumbar spine BMD in patients who were not treated with corticosteroids. However, among patients treated with prednisone > or = 5 mg/day, combined treatment with MTX and prednisone was associated with greater bone loss in the lumbar spine than treatment with prednisone without MTX.