Incidence of idiopathic pulmonary fibrosis in Korea based on the 2011 ATS/ERS/JRS/ALAT statement

OBJECTIVE: To estimate the annual incidence rate of interstitial lung disease (ILD) and idiopathic pulmonary fibrosis (IPF) in Korea. DESIGN: A retrospective cohort design using the Korean Health Insurance Review and Assessment Service (HERA) database spanned the period from January 2008 to December 2012. Patients with ILD and IPF were identified based on the International Classification of Disease-10 (ICD-10) diagnosis and procedure codes. Definition 1 is code J84 (ILD); Definition 2 is code J84 plus high-resolution computed tomography (HRCT), bronchoalveolar lavage (BAL) or lung biopsy; Definition 3 is code J84.1 (ILD with fibrosis); Definition 4 is code J84.1 and HRCT, BAL or lung biopsy; and Definition 5 is code J84.1A (IPF), and was specifically implemented for IPF. RESULTS: The incidence rates of lLD per 100 000 population based on Definitions 1-5 were respectively 48.5, 32.2, 16.2, 11.4 and 1.7. CONCLUSION: The incidence of ILD with fibrosis was approximately 23% of overall ILD incidence. IPF incidence was approximately 10% of the incidence of lLD with fibrosis. Based on the new ATS/ERS/JRS/ALAT statement published in 2011, the incidence rate of IPF was 1.7/100 000.