Clinical features and outcomes of patients with microscopic polyangiitis: experience of two centers

Background and Aim: Microscopic polyangiitis (MPA) is a rare necrotizing vasculitis that involves predominantly the small-caliber blood vessels. In this retrospective study, we aimed to evaluate the clinical findings, prognostic factors, and outcomes of MPA patients followed in two different centers.

Material and Method: In this retrospective study, a total of 38 patients diagnosed and followed with MPA in two different centers between January 2005 and December 2019 were included. Medical records of the patients were reviewed retrospectively. The diagnoses were based on the definition of MPA in the Chapel Hill consensus conference (CHCC-2012). In addition to the socio-demographic characteristics, clinical features, laboratory and immunological parameters; time passed for the diagnosis, treatment, outcomes, and follow-up time were recorded for each patient. The Five Factor Scores (FFS; Revised FFS 2009) and Birmingham Vasculitis Activity Score (BVAS; Version 3) were applied in all patients.

Results: In a total of 38 patients (10 females, 28 male) were included in the study. The mean age of the participants was 54.52 ± 8.21 (range: 32-74) years. The mean time passed for the diagnosis was 2.93 ± 2.03 (0.50-11) months and the mean follow-up period was 55.0 ± 30.51 (2-124) months. At admission, the mean BVAS was 18.28 ± 5.73 (8-35). The FFS results were as follows; 0 in 4 (10.5%) patients, 1 in 27 (71.1%) patients, 2 in 7 (18.4%) patients. The most common symptoms at admission were dyspnea, cough, and hemoptysis. Renal failure was present in 31 (81.5%) of the patients, at admission. The most common immunologic finding was the p-ANCA positivity in 26 (68.4%) patients. Among all patients, 25 (65.8 %) did not have any other attacks after the diagnosis. In follow-ups, 12 (31.5%) patients were passed away and vasculitis associated mortality rate was 18.4%. The effects of some factors on mortality including age ≥ 65 years, male gender, renal involvement, p-ANCA positivity, decreased oxygen saturation (< 90%), having anemia at admission, having FEV1/FVC < 70 in spirometry, having a FFS score of 2, and having a BVAS > 18 were examined (Table 6). Only having an FFS score of 2 and BVAS > 18 were determined as the factors significantly affecting mortality (P: 0.01).

Conclusion: Pulmonary symptoms are more predominant in MPA. Though many patients did not have any other attacks after the diagnosis, the vasculitis associated mortality may reach about 20%. BVAS and FFS are still the best determinants of mortality.

Microscopic polyangiitis; Autoimmune vasculitis; Birmingham Vasculitis Activity Score (BVAS); Five Factor Scores (FFS)

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