29. Interstitial Lung Disease in ANCA-Associated Vasculitis: Associated Factors, Radiographic Features, and Mortality
Creators: name: Doliner1, Brett
name: Rodriguez2, Karen
name: Montesi3, Sydney
name: Xiaoqing Fu4, 5
name: Sharma2, Amita
name: Zachary Wallace4, 5
Publisher: name: Zenodo
Year: 2022
Subjects: Vasculitis
ANCA
Abstracts
Giant Cell Arthritis
MPA
GPA
EGPA
Takayasu
IgA vasculitis

description: <strong>Background: </strong>Despite treatment advances, ANCA-associated vasculitis (AAV) remains associated with excess morbidity and mortality. Interstitial lung disease (ILD) is an increasingly recognized manifestation of AAV, but its prevalence, characteristics, and outcomes remain poorly defined. Additionally, most studies of AAV-ILD have been performed in AAV cohorts assembled in Asia where MPO-ANCA+ disease is highly prevalent. We sought to characterize factors associated with AAV-ILD and mortality in AAV-ILD in a large North American-based AAV cohort. <strong>Methods:</strong> AAV-ILD cases were identified by screening a consecutive inception PR3- or MPO-ANCA+ AAV multi-center cohort assembled between 2002 and 2019 for ICD-9/10 codes relevant to the diagnosis of ILD. Each case identified by this screen then underwent a manual review of the electronic health record (EHR) and available chest imaging. Two board-certified radiologists reviewed all available computer tomography (CT) scans of the chest for each patient to assess for interstitial lung disease and classify the type of ILD. Demographics, AAV disease features, results of pulmonary function tests, and comorbidities were extracted from the EHR. 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. Univariate analyses were used to assess the association of demographic- and disease-specific factors with AAV-ILD. Unadjusted and adjusted Cox proportional hazard models with age as the time scale were used to assess the association of AAV-ILD with death among patients with AAV. <strong>Results:</strong> Of 684 patients in the MGB AAV Cohort, 91 (13%) had ILD which preceded the diagnosis of AAV by a mean of 2.2 years (Table 1). AAV-ILD patients were older (67 vs 60 years, p&lt;0.001) than patients without ILD but the distribution of sex and race was similar. The proportion of ever smokers (57% vs. 50%, p=0.23) was similar among those with and without AAV-ILD. AAV-ILD patients were more often MPO-ANCA+ (93% vs. 65%, p&lt;0.001); among MPO-ANCA+ patients (n=470), 85 (18%) had ILD whereas 6 (3%) of 208 PR3-ANCA+ patients had ILD. The majority of ILD was fibrotic (76%) and UIP was the most common ILD type (40%). The mean baseline forced vital capacity (FVC) % predicted was 80.8% (19.6%) and the mean baseline DLCO % predicted was 56.2% (22.7%). Over 4,708 years of follow-up there were 37 deaths in the AAV-ILD group and 149 in the non-ILD group (incidence rates of 68.4 vs 35.8 / 1,000 person years). AAV-ILD was associated with a 47% higher risk of death (aHR 1.47, 95% CI 1.01, 2.15) compared to AAV patients without ILD. <strong>Conclusions:</strong> In a large North American cohort of AAV patients, we estimated the prevalence of AAV-ILD as 13% and observed strong associations with MPO-ANCA positive disease. Indeed, nearly 1 in 5 patients with MPO-ANCA+ AAV had ILD which is likely an underestimate given the retrospective nature of this study. In most cases, AAV-ILD was present prior to or at the time of AAV diagnosis, highlighting that it is a feature that may precede other manifestations of AAV. Compared with AAV patients without ILD, those with ILD have a higher risk of all-cause mortality. Additional studies are needed to understand appropriate screening approaches to ILD in this population and the response of ILD in AAV to conventional AAV treatment regimens. <strong>Disclosures:</strong> ZSW is supported by NIH/NIAMS [K23AR073334]. ZSW reports research support from Bristol-Myers Squibb and Principia/Sanofi and consulting fees from Viela Bio and Medpace.