Acute exacerbation of idiopathic pulmonary fibrosis: incidence, risk factors and outcome.

Although acute exacerbation of idiopathic pulmonary fibrosis (IPF) has become well recognised, the reported incidence and outcomes are highly variable, and risk factors are unknown. The aim of this study was to estimate the incidence, risk factors and impact of acute exacerbations, and other known causes of rapid deterioration. This was a retrospective review of 461 patients with IPF (269 cases were biopsy-proven). The median follow-up period was 22.9 months. Rapid deterioration requiring hospitalisation occurred in 163 (35.4%) patients, with multiple episodes in 42 patients. Acute exacerbation was the most frequent cause (55.2%), followed by infection. The 1- and 3-yr incidences of acute exacerbation were 14.2 and 20.7%, respectively. Never having smoked and low forced vital capacity (FVC) were significant risk factors. The in-hospital mortality rate was 50.0%, and the 1- and 5-yr survival rates from the initial diagnosis were 56.2 and 18.4%, respectively. Acute exacerbation was a significant predictor of poor survival after the initial diagnosis, along with increased age, low FVC and diffusing capacity of the lung for carbon monoxide, and steroid use with or without cytotoxic therapy. 1- and 3-yr incidences of acute exacerbation were 14.2 and 20.7%, respectively. Never having smoked and low FVC were risk factors. Acute exacerbation had a serious impact on the overall survival of the patients with IPF.