Clinical Characteristics and Prognostic Analysis of Microscopic Polyangiitis With Diffuse Alveolar Hemorrhage

Objective To analyze the clinical features and prognostic factors of microscopic polyangiitis (MPA) with diffuse alveolar hemorrhage (DAH).

Methods We conducted a retrospective study of 92 patients diagnosed with MPA with DAH at the First Affiliated Hospital of Chongqing Medical University between March 1, 2012, and March 12, 2018. The cumulative survival rate was analyzed by the Kaplan-Meier method, and survival curves were drawn. A Cox hazard model was used to determine the prognostic factors for survival by univariate and multivariate analysis.

Results The mean age at the onset of MPA with DAH was 66.32 years. Among the 92 MPA with DAH patients with follow-up visits, 41 (44.57%) were critically ill and 79 (85.87%) had pulmonary and renal involvement. The cumulative survival rates of the 92 patients at 1, 3, and 5 years were 63.7%, 51.2%, and 47.3%, respectively, and the median survival time was 46 months. In the multivariate analysis, age > 65 years (HR 4.30, 95% CI 1.94–9.55), sCr > 500 μmol/L (HR 2.04, 95% CI 1.05–3.97), PaO₂/FiO₂ < 300 mmHg (HR 4.10, 95% CI 1.97–8.53), and lung involvement area ≥ 50% (HR 2.93, 95% CI 1.40–6.13) were independent prognostic factors (P < 0.05).

Conclusion The incidence and mortality of DAH are high in MPA patients. Age > 65 years, sCr > 500 μmol/L, PaO₂/FiO₂ < 300 mmHg, and lung involvement area ≥ 50% are independent prognostic factors for MPA with DAH.