Increasing global mortality from idiopathic pulmonary fibrosis in the twenty-first century

Evidence from the United Kingdom suggests that the number of deaths from idiopathic pulmonary fibrosis is increasing, although comparable international data are limited.

We aimed to collate death certification data from multiple countries to determine global trends in mortality from idiopathic pulmonary fibrosis.

Data were obtained from the national statistics agencies of countries with relevant mortality records. Age-standardized mortality rates were calculated, and Poisson regression modeling was used to calculate rate ratios. Meta-analysis was used to calculate an overall estimate of mortality change over time.

Ten countries provided mortality data on pulmonary fibrosis over a period from 1999 to 2012. Age-standardized mortality ranged between 4 and 10 per 100,000 population for the most recent years of data, being lowest in Sweden (4.68 per 100,000), Spain (5.38 per 100,000), and New Zealand (5.55 per 100,000), and highest in the United Kingdom (9.84 per 100,000 in England and Wales, 10.71 per 100,000 in Scotland) and Japan (10.26 per 100,000). Positive associations with male sex and increasing age were consistently observed across all countries. There was an overall 2-3% annual increase in mortality depending on codes used for classification: For broad codes the overall rate ratio was 1.03 (95% confidence interval, 1.02-1.04; P < 0.001) and for narrow codes the overall rate ratio was 1.02 (95% confidence interval, 1.01-1.03; P < 0.001). Validation in a local cohort showed that idiopathic pulmonary fibrosis was recorded as the underlying cause of death in two-thirds of known cases and anywhere on the death certificate in 80% of cases.

Mortality from idiopathic pulmonary fibrosis is increasing steadily worldwide, despite the fact that death certification will almost certainly underestimate true mortality. We estimate that there will be between 28,000 and 65,000 deaths in Europe and between 13,000 and 17,000 deaths in the United States from idiopathic pulmonary fibrosis clinical syndrome in 2014. Variation between countries remains but is less than previously reported.