INTERSTITIAL LUNG DISEASE IN ANCA-ASSOCIATED VASCULITIS: ASSOCIATED FACTORS AND OUTCOMES
Authors: Brett Doliner et al.
Interstitial lung disease (ILD) is an increasingly recognized manifestation of AAV. Most studies of AAV-ILD have been performed in Asian AAV cohorts where MPO-ANCA+ disease is highly prevalent. This study reports about results of a large North American AAV cohort.
AAV-ILD cases were identified by screening a consecutive inception PR3- or MPO-ANCA+ AAV multi-center cohort assembled between 2002 and 2019. Scans were assessed for interstitial lung disease and classified according to the type of ILD (UIP vs non-UIP). Demographics, AAV disease features, results of pulmonary function tests, and comorbidities were extracted from the electronic health records. The baseline Birmingham Vasculitis Activity Score/Wegener’s Granulomatosis (BVAS/WG) was determined for each patient. All-cause mortality was assessed by linkage to the National Death Index.
684 patients were screened; 97 (14.2%) had AAV-ILD. Patients with AAV-ILD were older (67±12yrs vs 58±18yrs, p< 0.001) than those with AAV-non-ILD; sex distribution was similar (55% vs 60% female, p=0.7). AAV-ILD patients were more often MPO-ANCA+ (97% vs. 64%, p< 0.001) and showed less often head and neck involvement (31% vs 45%, p=0.01). The diagnosis of ILD preceded or occurred concurrently with the diagnosis of AAV in 85 (88%) patients. The ILD pattern was classified as UIP in 29 (30%) patients. AAV-ILD was associated with a 53% higher risk of death than AAV-non-ILD in analyses adjusted for age, sex, baseline BVAS/WG, and ANCA type (HR=1.53, 95% CI 1.05, 2.21).
In a large North American cohort of AAV patients, a prevalence of 14% for AAV-ILD was observed with a strong association with MPO-positivity. Compared with AAV patients without ILD, those with ILD have a higher risk of all-cause mortality. AAV-ILD was present prior to or at the time of AAV diagnosis in the majority of cases. The data suggest searching for ANCA-positivity in ILD of unknown etiology.