Abstract Rationale Interstitial Pneumonia with Autoimmune Features (IPAF) is a classification for patients with interstitial lung disease (ILD) who exhibit clinical, serologic, or morphologic features suggestive of connective tissue disease but do not meet criteria for a defined rheumatic disorder. While antifibrotics have shown benefit in other fibrosing ILD, their role in IPAF, especially in combination with immunosuppression, remains unclear. This study evaluates the impact of antifibrotics, immunosuppression, or their combination adjusted for fibrotic status (fibrotic vs non-fibrotic IPAF), on lung function decline, survival, and treatment response. Methods We performed a retrospective cohort study that included patients diagnosed with Interstitial Pneumonia with Autoimmune features (IPAF) seen at the University of Florida. We collected demographics, comorbidities, symptoms, serial pulmonary function tests, CT chest assessments. Patients were classified as Fibrotic or Non-fibrotic IPAF. Longitudinal distributions of FVC % and DLCO % were visualized through patient-level trajectories and group-level boxplots. Survival was assessed using Kaplan-Meier estimates and log-rank tests stratified by ILD subtype and treatment group. Results A total of 159 patients (52.2% male) were included, with a mean age of 69.2±10.2 years and majority were White (81.1%). Baseline lung function showed an average FVC of 69.4±18.6% and DLCO of 43.2±17.9%. Dyspnea (70.2%) and cough (52.8%) were common presenting symptoms, and overall mortality was highest in the Pred/Myco/Aza (42.2%) and Immunosuppression + Antifibrotic (45.8%) groups. Across all groups, the adjusted association between fibrotic status and ΔFVC %/year was not statistically significant (p0.05), though antifibrotic users showed a trend toward slower FVC decline (β ≈ +8 % per year, p = 0.053). Median survival times were broadly similar between fibrotic and non-fibrotic subtypes within each therapy group. Kaplan-Meier curves suggested numerically lower early survival in fibrotic IPAF, most notably in the immunosuppression + antifibrotic group (χ² = 2.91, p = 0.088). Across all medication strategies, trajectories demonstrated heterogeneity, reflecting variable disease behavior and treatment response. Conclusions Survival outcomes were generally similar across subtypes and treatment groups, though early survival appeared lower in fibrotic IPAF patients receiving combination therapy. Overall, the variability in disease trajectories highlights the heterogeneity of IPAF and its response to treatment. This abstract is funded by: None
Manjarres et al. (Fri,) studied this question.