Efficacy of Methotrexate in Real-world Management of Giant Cell Arteritis: A Case-control Study

Objective. To determine the effect of methotrexate (MTX) on relapse risk and glucocorticoid (GC) use in a large single-institution cohort of patients with giant cell arteritis (GCA). Methods. Patients diagnosed with GCA from 1998 to 2013 with confirmed evidence of temporal artery biopsy and/or radiographic evidence of large vessel vasculitis were identified. Each patient with GCA treated with adjunct MTX (case) was matched to a similar patient with GCA treated only with GC (control). GC requirements and relapse events before and after MTX initiation (or corresponding index date) were compared using rate ratios (RR). Results. Eighty-three cases and 83 controls were identified and compared. No significant differences in age, demographics, laboratory variables, baseline disease characteristics, or mean initial prednisone doses were observed. Median [interquartile range (IQR)] time from GCA diagnosis to MTX initiation in cases was 39 (13-80) weeks and the median (IQR) starting dose was 13.5 (10-15) mg/week. RR comparing relapse rates before and after MTX initiation/index date were significantly reduced in both cases (RR 0.32, 95% CI 0.24-0.41) and controls (RR 0.60, 95% CI 0.43-0.86). The decrease in relapse rate was significantly greater in patients taking MTX than in those taking GC alone (p = 0.004). Rates of GC discontinuation did not differ between groups. Conclusion. In this large single-institution cohort, the addition of MTX to GC decreased the rate of subsequent relapse by nearly 2-fold compared to patients taking GC alone. MTX may be considered as adjunct therapy in patients with GCA to decrease the risk of further relapse events.