Koki Nakamura, Shuhei Shimoyama, Nobuya Abe, Satoshi Yabusaki, Tetsuya Horita
In this real-world ILD cohort, CTD-ILD and IPAF were associated with better survival than IIP/IPF; however, the association was not retained in complete-case analysis. Baseline IST exposure was associated with survival. Key Points • Prognostic impact of autoimmune background in ILD on everyday clinical situations has not been clarified. • CTD-ILD and IPAF were associated with better survival than IIP/IPF in a real-world ILD cohort. • Baseline IST exposure was associated with survival in ILD.
INTRODUCTION: The real-world prognostic differences among connective tissue disease-associated interstitial lung disease (CTD-ILD), interstitial pneumonia with autoimmune features (IPAF), and interstitial pneumonia/idiopathic pulmonary fibrosis (IIP/IPF) remain uncertain, and the prognostic impact of baseline immunosuppressive treatment (IST) and radiologic disease extent are also unclear. We aimed to investigate whether autoimmune background was associated with survival in ILD and to identify prognostic factors at diagnosis.
METHOD: This single-center retrospective cohort study involved 566 patients with ILD who underwent high-resolution computed tomography (HRCT). Patients were classified into CTD-ILD, IPAF, or IIP/IPF. Survival was assessed using Kaplan-Meier methods and Cox models. Missing data were addressed with multiple imputations.
RESULTS: The CTD-ILD and IPAF groups showed better survival than IIP/IPF group. In the primary multivariable model using multiple imputation, ordinal ILD classification was associated with survival (hazard ratio [HR]: 0.75, 95% confidence interval [CI]: 0.59-0.95). Older age (HR: 1.03, 95% CI: 1.02-1.05), male sex (HR: 1.88, 95% CI: 1.27-2.79), and diffuse alveolar damage pattern (HR: 2.85, 95% CI: 1.35-6.00) were associated with higher mortality, whereas higher forced vital capacity (HR: 0.98, 95% CI: 0.97-0.99) and baseline IST exposure (HR: 0.51, 95% CI: 0.32-0.83) were associated with better survival. HRCT-derived ILD extent was not associated with mortality. In complete-case analysis, ILD classification was not associated with survival.
CONCLUSIONS: In this real-world ILD cohort, CTD-ILD and IPAF were associated with better survival than IIP/IPF; however, the association was not retained in complete-case analysis. Baseline IST exposure was associated with survival. Key Points • Prognostic impact of autoimmune background in ILD on everyday clinical situations has not been clarified. • CTD-ILD and IPAF were associated with better survival than IIP/IPF in a real-world ILD cohort. • Baseline IST exposure was associated with survival in ILD.