Effect of low dose methotrexate on bone density in women with rheumatoid arthritis: results from a multicenter cross-sectional study.

Objective: To analyze the influence of low dose methotrexate (MTX) on bone using data from a large multicenter, cross-sectional study on bone mineral density (BMD) in women with rheumatoid arthritis (RA).
Methods: We selected 731 female patients with RA divided into 2 groups on the basis of MTX use: never MTX users (n = 485) and MTX users for at least 6 months (n = 246). Demographic, disease, and treatment related variables were collected for each patient. BMD was measured at lumbar spine and proximal femur by dual energy x-ray absorptiometry. Osteoporosis was defined as BMD < -2.5 T-score.
Results: The frequency of osteoporosis among never MTX users and MTX users was 29.1% and 28.3% (p = NS) for lumbar spine, and 34.8% and 37.8% (p = NS) for femoral neck, respectively. Mean T-score values at lumbar spine and femoral neck were comparable in the 2 groups, even after adjusting for age, menopausal status, body mass index (BMI), Health Assessment Questionnaire (HAQ) score, and steroid use. The generalized linear model showed that age, menopause, BMI, HAQ score, and steroid use were significant independent predictors of BMD at lumbar or at femoral level, whereas MTX use was not. Logistic procedure showed that only age, HAQ score, and BMI were significantly associated with the risk of osteoporosis.
Conclusion: We found no negative effect of low dose MTX on BMD in women with RA.