Nationwide Incidence and Prevalence of Idiopathic Pulmonary Fibrosis in South Korea

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease with high mortality. Population-based data on long-term epidemiological trends and real-world treatment outcomes in Asia remain limited. This study described national trends in IPF prevalence and incidence in South Korea and evaluated pirfenidone use and associated mortality. METHODS: Using the Korean National Health Insurance Service customized research database, we identified prevalent IPF cases from 2010 to 2023 and incident cases from 2011 to 2023. IPF was defined using the International Classification of Diseases, 10th Revision, and rare incurable disease codes, based on a predefined operational definition. Among incident cases, the association between pirfenidone use and all-cause mortality was assessed using multivariable-adjusted Cox proportional hazards models. RESULTS: A total of 91,638 prevalent and 28,683 incident IPF cases were identified during the study period. The crude prevalence increased from 8.91 per 100,000 persons ≥50 years in 2010 to 63.78 per 100,000 in 2023. The crude incidence increased from 6.07 per 100,000 in 2011 to 16.86 per 100,000 in 2023. Similar increasing patterns were observed for age- and sex-standardized rates. IPF was more common in men, and demonstrated a pronounced age gradient. Following reimbursement approval, pirfenidone use increased substantially. Pirfenidone use was associated with a reduced risk of all-cause mortality (adjusted hazard ratio, 0.627; 95% confidence interval, 0.600-0.665), with progressively stronger associations observed with longer treatment duration. CONCLUSION: The burden of IPF in South Korea has increased over the past decade, during which expanded real-world pirfenidone use was associated with improved survival.