Granulomatosis with polyangiitis (Wegener's): impact of maintenance therapy duration

To determine outcomes in relation to duration of maintenance therapy in patients with granulomatosis with polyangiitis (Wegener's) (GPA), we conducted a retrospective chart review of patients with GPA seen at a single vasculitis center from 1992 to 2010. All patients achieved remission defined by a Birmingham Vasculitis Activity Score for Wegener Granulomatosis (BVAS/WG) of 0 with either cyclophosphamide or methotrexate. After achieving remission all patients were started on maintenance therapy with either methotrexate or azathioprine.The study comprised 157 patients with a median follow-up of 3.1 years. Using a univariate model, the continuation of maintenance medications for >18 months showed a 29% reduction in hazard ratio (HR) for relapse (HR, 0.71; 95% confidence interval [CI], 0.42-1.19; p = 0.19). Treatment for >36 months showed a 66% reduction in hazard ratio for relapse (HR, 0.34; 95% CI, 0.15-0.76; p = 0.008). When length of treatment was considered as a continuous factor, longer courses had an inverse relationship with the risk of relapse (HR, 0.70; 95% CI, 0.58-0.84; p < 0.001), which remained significant after adjusting for prednisone dose (HR, 0.59; 95% CI, 0.42-0.83; p = 0.003). Fifty-two percent of relapses occurred while the patients were off maintenance therapy. Among all patients who relapsed on therapy, 52% of those receiving methotrexate were on <15 mg/week, and 67% of those receiving azathioprine were on ≤ 50 mg/d. There were no differences between the short- and long-term maintenance therapy groups in overall adverse events or GPA-related morbidity.Discontinuation or use of low doses of maintenance therapy is associated with a higher relapse rate.