Acute exacerbation of idiopathic pulmonary fibrosis: outcome and prognostic factors.

BACKGROUND Acute exacerbation is a substantial cause of death in patients with idiopathic pulmonary fibrosis with poorly described prognostic factors. OBJECTIVES To review the features associated with acute exacerbation of idiopathic pulmonary fibrosis and assess its prognostic factors. METHODS Thirty-seven occurrences of acute exacerbation of idiopathic pulmonary fibrosis were retrospectively reviewed in the medical records of 27 patients. Clinical presentation, radiographic studies, pulmonary function tests, laboratory data, treatment, and outcome were analyzed. RESULTS Acute exacerbation of idiopathic pulmonary fibrosis occurred more frequently between December and May (75.7%) than between June and November (24.3%) (p = 0.01). In-hospital mortality was 27% and median survival was 4.2 months (range 0.2-36.6). Significant differences between nonsurvivors and survivors included the time elapsed between their admission and the initiation of treatment for acute exacerbation (6 vs. 3.1 days, p = 0.04), lactate dehydrogenase levels at admission (801 vs. 544.6 IU/l, p = 0.002), impairment of the prior forced vital capacity (51.2 vs. 65%, p = 0.01) and diffusing capacity for carbon monoxide (21.7 vs. 34%, p = 0.01). Furthermore, the evolution of gas exchange in the first 10 days after the initiation of treatment was associated with in-hospital and long-term mortality. CONCLUSIONS Acute exacerbations of idiopathic pulmonary fibrosis are more frequent during winter and spring. The time between admission and initiation of treatment is a new reported prognostic factor that should be investigated further. This finding highlights the need for a fast diagnostic approach that should probably be standardized. Early gas exchange modifications reflect the response to treatment and predict the prognosis.