No association between methotrexate and impaired bone mineral density in a cohort of patients with polymyalgia rheumatica, giant cell arteritis, granulomatosis with polyangiitis and other vasculitides—a cross-sectional analysis with dose–response analyses

Objective To investigate whether methotrexate (MTX) use is associated with bone mineral density (BMD) in patients with polymyalgia rheumatica (PMR) and various forms of vasculitis. Methods Rh-GIOP is a cohort study designed to evaluate bone health in patients with inflammatory rheumatic diseases. This cross-sectional analysis assessed the baseline visits of all patients with PMR or any kind of vasculitis. Following univariable analysis, multivariable linear regression analysis was performed. The lowest T-score of either the lumbar spine or the femur was chosen as the dependent variable to examine the relationship between MTX use and BMD. These analyses were adjusted for a variety of potential confounders, including age, sex, and glucocorticoid (GC) intake. Results Of 198 patients with PMR or vasculitis, 10 patients were excluded for very high GC dose (n = 6) or short disease duration (n = 4). The remaining 188 patients had the following diseases: PMR 37.2%, giant cell arteritis 25.0%, granulomatosis with polyangiitis 16.5%, followed by rarer diseases. The mean age was 68.0 ± 11.1 years, mean disease duration was 5.58 ± 6.39 years, and 19.7% had osteoporosis by dual x-ray absorptiometry (T-score ≤ −2.5). 23.4% were taking MTX at baseline with a mean dose of 13.2 mg/week (median: 15 mg/week). 38.6% of those used a subcutaneous preparation. MTX users had similar BMD compared to non-users (minimum T-scores −1.70 (± 0.86) versus −1.75 (± 0.91), respectively; p = 0.75). There was no statistically significant dose–response relationship: neither current nor cumulative dose were associated with BMD in unadjusted or adjusted models (current dose: slope −0.02; −0.14 to 0.09; p = 0.69; cumulative dose: slope −0.12; −0.28 to 0.05; p = 0.15). Conclusion In the Rh-GIOP cohort, MTX is used in about a quarter of patients with PMR or vasculitis. It is not associated with BMD levels.