Interstitial lung disease in patients with antineutrophil cytoplasmic antibody-associated vasculitis: chest CT patterns and correlation with survival

Abstract

Background

Interstitial lung disease (ILD) is common in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), with usual interstitial pneumonia (UIP) being the most frequent pattern. The impact of different ILD patterns on clinical outcomes remains unclear.

Methods

Retrospective cohort study included patients with AAV (MPA and GPA) and ILD confirmed by chest CT scans between 1997 and 2021. ILD patterns were classified according to 2018 Fleischner Society criteria.

Results

Of 1862 patients in the Mayo AAV Cohort, 143 (7.7 %) had ILD on chest CT. The median age at the time of ILD diagnosis (occurring before AAV diagnosis in 26.6 %) was 69 years (IQR 61–75); 60 % were male, and 75 % were MPO-positive. On chest CT, “typical UIP” pattern was identified in 44 patients (30.8 %), whereas 13 (9.1 %) manifested “probable UIP” pattern, 37 (25.9 %) “indeterminate for UIP” pattern, and 49 (34.3 %) “non-UIP” pattern. Among MPO-ANCA patients, typical UIP pattern was most common (37.4 %), while non-UIP pattern was most common (58.3 %) among PR3-ANCA patients. Patients with typical UIP pattern, when compared to those with non-UIP pattern, were more commonly male (70.5 %), MPO-ANCA (90.0 %), diagnosed before the onset of AAV (40.9 %), and had reduced diffusion capacity on pulmonary function tests. The presence of typical UIP was related with higher survival at 12 months and 10 years in MPO-ANCA patients when compared to other ILD patterns (IRR 8.201 and IRR 2.179).

Conclusions

The typical UIP pattern in AAV-ILD is associated with better survival, particularly in MPO-ANCA patients, suggesting distinct mechanisms for ILD development in MPO vs. PR3-AAV.