Relation of FEV₁ to clinical outcomes during exacerbations of chronic obstructive pulmonary disease

FEV₁ is an objective measure of airflow obstruction used in clinical practice and in therapeutic trials. The precise relationship of FEV₁ to clinical outcomes is generally uncertain. As part of a randomized trial to assess systemic corticosteroid efficacy, we obtained serial FEV₁ measurements in patients hospitalized for exacerbations of chronic obstructive pulmonary disease (COPD). Over the first 14 Study Days at least one FEV₁ value was obtained in 261 subjects. Sixty-four of these subjects experienced treatment failure, defined as death, intubation, readmission for COPD, or intensification of drug therapy, by Study Day 30. After adjustment, both FEV₁ at entry into the study (odds ratio [OR] for a 100-ml increase, 0.87; 95% confidence interval [CI], 0.79 to 0.96) and change in FEV₁ over the first two Study Days (OR for a 100 ml increase, 0.80; 95% CI, 0.69 to 0.92) predicted treatment failure. We identified no baseline characteristic that was significantly related to FEV₁ at entry into the study. Assignment to the systemic corticosteroid treatment arm was associated with a significantly larger FEV₁ at Study Day two (p = 0.01). We conclude that FEV₁ measurements at admission and over the first several days of hospitalization are highly predictive of clinical outcomes during exacerbations of COPD.