The natural history of idiopathic pulmonary fibrosis in a large European population: the role of age, sex and comorbidities.

Placebo arms of clinical trials provide an opportunity to investigate the natural history of idiopathic pulmonary fibrosis (IPF) but these patients are not representative of the real life IPF population. Objective of this article is to evaluate patients' characteristics of incident IPF cases and their impact on mortality and hospitalizations risk. We conducted a retrospective cohort study using data from administrative databases from 2000 to 2010. Based on different algorithms reported in literature, incident IPF cases were identified. We applied Cox proportional hazards models to assess relationship between patients' characteristics, mortality and hospitalization. According to three case definitions, we identified 2338, 460 and 1704 incident IPF cases. Mean age at diagnosis was about 72 years, the proportion of male varied between 59 and 62% and patients with at least one chronic disease were between 70 and 74%. Age, male sex and comorbidities were associated to worse outcomes. Congestive heart failure (CHF), diabetes and cancer were conditions associated to mortality, while those associated to hospitalization were CHF and chronic obstructive pulmonary disease. Our data source provided one of the largest samples of unselected patients with a long follow-up period. Using different algorithms proposed and validated in literature, we observed that mortality and hospitalization rate are high in patients with IPF and age, sex and comorbidities significantly affect clinical outcomes. Females show a significant survival advantage over males, even after adjusting for age and comorbidities. Patients with pre-existing diseases, especially those with pulmonary and cardiovascular diseases are at higher risk.