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

FEV1 is an objective measure of airflow obstruction used in clinical practi ce and in therapeutic trials. The precise relationship of FEV1 to clinical outcomes is generally uncertain. As part of a randomized trial to assess sy stemic corticosteroid efficacy, we obtained serial FEV1 measurements in pat ients hospitalized for exacerbations of chronic obstructive pulmonary disea se (COPD). Over the first 14 Study Days at least one FEV1 value was obtaine d in 261 subjects. Sixty-four of these subjects experienced treatment failu re, 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 int erval [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 re lated to FEV1 at entry into the study. Assignment to the systemic corticost eroid treatment arm was associated with a significantly larger FEV1 at Stud y Day two (p = 0.01). We conclude that FEV1 measurements at admission and o ver the first several days of hospitalization are highly predictive of clin ical outcomes during exacerbations of COPD.