A multi-site study including the University of Kentucky College of Public Health outlines a new approach for identifying patients with undiagnosed Chronic Obstructive Pulmonary Disease (COPD).
[Photo: Dr. David Mannino]
Researchers conducted a multi-site, cross-sectional, case-control study in U.S. pulmonary and primary care clinics that recruited subjects from primary care settings. Cases were patients with COPD and at least one exacerbation in the past year or FEV1 (the amount of air the patient can forcefully blow out of their lungs in one second) less than 60 percent of predicted without exacerbation in the past year. Control subjects were persons with no COPD or with mild COPD (FEV1 ≥60 percent predicted, no exacerbation in the past year). In random forests analyses, researchers identified the smallest set of questions plus peak expiratory flow (PEF) with optimal sensitivity (SN) and specificity
PEF and spirometry were recorded in 186 cases and 160 control subjects. The mean (SD) age of the sample population was 62.7 (10.1) years; 55 percent were female; 86 percent were White; and 16 percent had never smoked. The mean FEV1 percent predicted for cases was 42.5 percent (14.2 percent); for control subjects, it was 82.5 percent (15.7 percent). A five-item questionnaire, CAPTURE (COPD Assessment in Primary Care to Identify Undiagnosed Respiratory Disease and Exacerbation Risk), was used to assess exposure, breathing problems, tiring easily, and acute respiratory illnesses. CAPTURE exhibited an SN of 95.7 percent and an SP of 44.4 percent for differentiating cases from all control subjects, and an SN of 95.7 percent and an SP of 67.8 percent for differentiating cases from no-COPD control subjects. The PEF (males, <350 L/min; females, <250 L/min) SN and SP were 88.0 percent and 77.5 percent, respectively, for differentiating cases from all control subjects, and they were 88.0 percent and 90.8 percent, respectively, for distinguishing cases from no-COPD control subjects. The CAPTURE plus PEF exhibited improved SN and SP for all cases versus all control subjects (89.7 percent and 78.1 percent, respectively) and for all cases versus no-COPD control subjects (89.7 percent and 93.1 percent, respectively).
The researchers conclude that CAPTURE with PEF can identify patients with COPD who would benefit from currently available therapy and require further diagnostic evaluation.
Dr. David Mannino, professor and chair, department of preventive medicine and environmental health, was an author on the paper, which was published in the American Journal of Respiratory and Critical Care Medicine.