Clinical presentation and long-term outcome of 144 patients with microscopic polyangiitis in a monocentric German cohort

Objective. To evaluate the clinical presentation and long-term outcome of a vasculitis centre cohort of patients with microscopic polyangiitis (MPA) with respect to organ manifestations, treatment, chronic damage and mortality. Methods. We performed a retrospective chart review at our vasculitis referral centre. MPA patients admitted between 1991 and 2013 classified by a modified European Medicines Agency algorithm were diagnosed and treated according to a standardized interdisciplinary approach. Results. Comprehensive data from standardized interdisciplinary workups was available for 144 patients (median follow-up 72 months). The overall standardized mortality ratio was 1.40 (95% CI 0.91, 2.07; P = 0.13). We observed a higher mortality [hazard ratio (HR) 4.04 (95% CI 1.21, 13.45), P = 0.02] in 17 patients with MPA-associated fibrosing interstitial lung disease (ILD) and 56 patients with peripheral nervous system involvement [HR 5.26 (95% CI 1.10, 25.14), P = 0.04] at disease onset. One hundred and fifteen patients (79.9%) responded to the initial treatment. Sixty-one (42.3%) achieved complete remission and 54 (37.5%) achieved partial remission. Twenty (13.9%) showed a refractory disease course. Conclusion. MPA patients at our tertiary rheumatology referral centre seemed to have a less severe phenotype resulting in a less severe disease course and better outcome than reported in other cohorts. Fibrosing ILD was significantly associated with mortality in this cohort.