B41-01 Comparison of Patients Hospitalized With Systemic Autoimmune Related Disease Interstitial Lung Disease in Relation to the Presence of a Defined Rheumatologic Illness

Abstract Rationale Interstitial lung disease (ILD) is a common complication of a wide variety of systemic autoimmune diseases (SARD) and acute exacerbations of SARD-ILD (AE-SARD-ILD) requiring hospitalization are associated with increased morbidity and mortality. However, it is unclear whether patients with positive autoimmune antibodies and ILD represent a different disease entity or are on the spectrum of SARD-ILD. We aim to determine whether outcomes of acute exacerbations differ between patients with a rheumatologist-defined diagnosis and those with undifferentiated SARD-ILD. Methods Temple University Hospitals electronic medical record was used to identify patients who were admitted for AE-SARD-ILD from 2016-2025. Identified patients were classified based on whether they had a rheumatology defined SARD-ILD or an undifferentiated ILD with a positive autoimmune antibody. Baseline demographic data and outcomes were obtained including average daily steroid dose, need for intensive care unit (ICU) admission, extracorporeal membrane oxygenation (ECMO), and transplant free survival during the admission. Chi square analysis and Mann-Whitney U testing were performed. Results A total of 51 patients were identified. 39/51 (76.5%) patients had a rheumatology defined illness consisting of 21.5% rheumatoid arthritis, 21.5% inflammatory myositis, 19.6% scleroderma, 5.9% Sjögren’s syndrome, 5.9% mixed connective tissue disease, and 2.0% systemic lupus erythematous. The remaining 12/51 (23.5%) had an undifferentiated autoimmune ILD. In the rheumatology defined ILD group, average daily steroid use was 28.4 mg, 53.8% required ICU admission, 17.9% required ECMO support, and transplant free survival was 69.2%. In the undifferentiated autoimmune ILD group, average daily steroid use was 18.3 mg (p = 0.039), 83.3% required ICU admission (p = 0.067), 16.7% required ECMO support (p = 0.919), and transplant free survival was 41.7% (p = 0.084). Conclusion Average daily steroid dose was higher in the rheumatology defined SARD-ILD group, and these patients trended toward increased transplant free survival. These findings may suggest that patients with undifferentiated SARD-ILD should be treated with similar steroid regimens as rheumatology defined SARD-ILD when experiencing an acute exacerbation. Although not definitive, this is hypothesis generating and highlights the need for prospective studies. Future directions include quantitative computed tomography (CT) analysis to further classify these patients. This abstract is funded by: None