Lung Involvement Patterns in ANCA-Associated Vasculitis: a Retrospective Study

Background. Pulmonary involvement in antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) is an important cause of mortality. The main variants of AAV are granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). Aims — to define the prevalence of pulmonary involvement in AAV patients and describe its computed tomography (CT)-patterns. Methods. A retrospective study was conducted. The study included patients with GPA and MPA. The diagnosis was established in accordance with the American College of Rheumatology (1990) criteria of GPA or the Chapel-Hill (2012) conference AAV definitions, as well as the classification criteria of GPA and MPA of the American College of Rheumatology and the European Alliance of Associations for Rheumatology (2022). All patients underwent chest CT. The primary endpoint was lung involvement, as determined by the results of a clinical and instrumental examination. Results. 243 patients (median age of onset 49.0 (35.0; 59.0); 167 (68.7%) women) with AAV were included in the study, including 171 with GPA and 72 with MPA. Lung damage was established in 175 (72.0%) patients (121 (70.8%) in GPA and 54 (75.0%) in MPA). The following variants of pulmonary involvement in AAV were registered: parenchymal infiltrates — 103 (58.9%); alveolar hemorrhage — 33 (18.9%); nodular disease — 58 (33.1%); cavities — 28 (16.0%); subclinical interstitial lung disease (ILD) — 43 (24.6%); ILD — 8 (4.6%); signs of fibrosis — 135 (77.1%); bronchiectasis — 24 (13.7%); and pleural effusion — 3 (1.7%). In GPA patients, cavities were more prevalent (p 0.001), so alveolar hemorrhage was in MPA (p 0.001). PR3-ANCA (OR: 3.25; 95% CI: 1.40–7.49) and general symptoms (fever, weight loss) (OR: 2.41; 95% CI: 1.28–4.54) were associated with pulmonary damage according to the logistic regression model. Conclusions. Pulmonary involvement in AAV is frequent. Among 243 patients with MPA and GPA who underwent a CT scan of the chest, 72% had lung abnormalities. These findings may have important implications for the diagnosis and management of AAV lung manifestations.