Effect of add-on methotrexate in polymyalgia rheumatica patients flaring on glucocorticoids tapering: a retrospective study.

Guidelines on management of polymyalgia rheumatica (PMR) recommend early introduction of methotrexate (MTX), especially in patients with worse prognosis, although evidence on clinical efficacy of MTX in PMR is limited. Our objective was to assess MTX efficacy in real-world PMR care. Retrospective data of newly diagnosed PMR patients who started MTX were compared to control patients in whom MTX was not started at the first flare. Main outcomes were number of flares per year (Poisson regression) and weighted daily glucocorticoid (GC)-dose (linear regression), and flare incidence rate ratio in the MTX group only. 240 patients were selected; 39 patients in the MTX group and 201 in the control group. The yearly incidence rate ratio of flares in the MTX versus control group was 0.80 (95% CI 0.45-1.42). The yearly flare rate was 1.22 before and 0.43 after MTX initiation, resulting in an incidence ratio of 0.35 (95% CI 0.23-0.52). Adjusted time weighted daily GC dose was higher in the MTX versus control group (ratio 1.37, 95% CI 1.04-1.80). No clear effect of MTX on flares was found and time weighted daily GC dose was higher, possibly due to residual confounding by indication. However, the clearly reduced flare rate after MTX start might be suggestive for a beneficial effect of MTX.