The rising incidence of idiopathic pulmonary fibrosis in the U.K.

BACKGROUND: Previous studies have shown that the incidence of idiopathic pulmonary fibrosis (IPF) is rising in the U.K. and U.S.A. Death registrations and primary care data were used to determine the current trends in IPF incidence in the U.K. Because routine clinical data sets were used, the term IPF clinical syndrome (IPF-CS) is used to describe individuals in this study.

METHODS: Age- and stratum-specific death registration rates between 1968 and 2008 were calculated and these were applied to the 2008 population to generate annual standardised expected number of deaths. Annual mortality rate ratios were calculated using Poisson regression. Computerised primary care records were used to determine incidence rates of IPF-CS between 2000 and 2008 stratified by age, sex and geographical region, and survival rates between calendar periods were compared.

RESULTS: Annual death certificate recording of IPF-CS rose sixfold across the study period from 0.92 per 100,000 in the 1968-1972 calendar periods to 5.10 per 100,000 in the 2006-2008 calendar period, and were higher in men and the older age groups. The incidence of IPF-CS in primary care increased by 35% from 2000 to 2008, with an overall incidence rate of 7.44 per 100,000 person-years (95% CI 7.12 to 7.77). Incidence was higher in men, the older population and in Northwest England.

CONCLUSIONS: The incidence of IPF-CS in primary care and registered deaths from this cause in the U.K. continues to rise in the 21st century. The current findings suggest that there are >5000 new cases diagnosed each year in the U.K.