Idiopathic pulmonary fibrosis in Taiwan - a population-based study

Background: This study took advantage of a large population-based database of the Taiwan National Health Insurance (NHI) to investigate the epidemiology of idiopathic pulmonary fibrosis (IPF) in Taiwan.

Methods: This is a retrospective cohort study based on secondary analysis of prospectively collected data in the NHI system and governmental data on death registry in Taiwan during 1997-2007. By using the broad and narrow definitions for IPF, we estimated incidence and prevalence rates of IPF, and its associated clinical outcomes.

Results: The estimates of annual IPF incidence rates became more stable after 2000, ranging between 0.9 and 1.6 cases per 100,000 persons. The prevalence rates became more than twofold from 2000 to 2007 (from 2.8 to 6.4 cases per 100,000 persons for the broad definition, and from 2.0 to 4.9 cases per 100,000 persons for the narrow definition). Men of age older than 75 years had markedly higher incidence and prevalence rates than other groups. Around 40% of all incidences and about 30% of prevalent cases occurred in this population group. The median survival time after IPF diagnosis was 0.9 year (interquartile range (IQR), 0.2-2.5 years) and 0.7 year (IQR, 0.1-2.3 years) for the broad and narrow definitions, respectively. Progression of IPF was the leading cause of death, followed by cancer.

Conclusions: In Taiwan, elderly men were the major group suffering from IPF. Survival time was short after IPF diagnosis, and the poor survival was largely attributable to quick IPF progression after diagnosis.