C39-35 Risk Factors Associated With Poor Outcomes in Acute Exacerbations of Interstitial Lung Disease Secondary to Viral Respiratory Infections

Abstract Rationale Patients with diffuse interstitial lung disease (ILD) may develop acute ILD (AE-ILD) exacerbations with an estimated annual incidence of 4% to 20%. These events are associated with high morbidity and mortality. Evidence is minimal when acute exacerbations of ILD are secondary to viral respiratory tract infections. Understanding prognostic factors in this group is essential to improve risk stratification and clinical management. Our objective was to identify risk factors associated with poor outcomes in patients with AE-ILD secondary to viral respiratory infections (VRI). Methods This is a single-center, retrospective cohort study of hospitalized patients with AE-ILD secondary to VRI between 2022 and 2024. The infectious process was confirmed by the BioFire Respiratory Panel 2.1. Demographic and clinical variables, pulmonary function tests, and fibrosis extent quantified by the Goh index were registered. Factors associated with mortality were evaluated using Cox proportional hazards models. Results Fifty-eight patients were included (63% male; mean age 62 years), 53% with connective tissue disease–associated ILD. The most frequently identified viruses were enterovirus/rhinovirus (34.5%), SARS-CoV-2 (17.2%), and respiratory syncytial virus (15.5%). Forty-five percent of the patients died during hospitalization. The extent of fibrosis before the acute exacerbation, quantified by the Goh score, was associated with mortality (HR 1.07, 95% CI: 1.02–1.12, p = 0.003). Higher baseline diffusing capacity was associated with lower mortality (HR 0.97; 95% CI 0.94–0.99; p = 0.014). Another risk factor associated with mortality was the use of ≥ 3 L/min of supplemental oxygen before AE-ILD (p = 0.003). Among those patients who survived, the rate of decline of FVC was -135 ml. Conclusion Mortality is high in patients with AE-ILD (45%). Risk factors related to disease severity such as the extent of ILD fibrosis, impaired DLCO, and the need for supplemental oxygen prior to exacerbation—are associated to mortality. Even among survivors, a significant decline in FVC was observed during follow-up. This abstract is funded by: None