Background: The aim of this study was to identify the percentage of undiagnosed patients with COPD through the implementation of an active search strategy in a selected subject population.
Methods: An observational, cross-sectional, multicenter study was conducted in a primary care setting in Spain. General practitioners gave their diagnostic impression of COPD (yes/no) on the basis of clinical criteria of subjects with respiratory symptoms and tobacco exposure. Subsequently, post-bronchodilator spirometry and quality-of-life tests were performed. Multivariate logistic regression techniques using receiver operating characteristic (ROC) curves were used to identify the combination of variables that best discriminates COPD.
Results: A total of 2,758 patients were screened at 368 primary care centers, of which 1,725 patients were included in the study. Seven hundred and ninety-three patients (46%) were diagnosed with COPD. Clinical judgment resulted in suspected COPD in 1,393 (81%) of the subjects. The best variables to discriminate COPD were a history of lower respiratory tract infections, cough, and dyspnea. This combination identified COPD with a ROCAUC of 0.61 denoting a poor discriminative ability.
Conclusion: Employing an active search strategy leads to a new COPD diagnosis in almost half of the subjects. Screening of COPD with post-bronchodilator spirometry should be considered mandatory for any high-risk subject visiting the general practitioner clinic for any reason.
Keywords: COPD; post-bronchodilator spirometry; primary care; screening.