Staging of Acute Exacerbation in Patients with Idiopathic Pulmonary Fibrosis

The purpose of this study was to evaluate the predictors of a 3-month mortality rate of acute exacerbation of idiopathic pulmonary fibrosis (IPF) and provide a new staging system. A total of 594 patients with IPF were included in this retrospective, observational study conducted from January 2001 to December 2010 at Okinawa Chubu Hospital. Among the 594 patients, 58 (9.8 %) developed acute exacerbation (AE) of IPF during the 10-year observation period. The median follow-up period for AE was 10.4 months. In-hospital mortality was 56.9 % and the 3-month mortality rate was 63.8 %. We identified the following four parameters in a multivariate analysis as: serum lactate dehydrogenase, sialylated carbohydrate antigen (KL-6), ratio of partial pressure of oxygen and fraction of inspiratory oxygen, and total extent of abnormal findings on high-resolution computed tomography of the chest. Patients were divided into two groups on the basis of the four composite parameters. Patients in the extensive disease-stage group required more mechanical ventilation and intensive therapy than those in the limited disease-stage group. The 3-month mortality rate was higher in patients in the extensive disease-stage group than in patients in the limited disease-stage group (80.6 vs. 54.5 %, respectively; p = 0.007). Staging of AE in patients with IPF provided useful information regarding disease severity and short-term outcome.