Detection of COPD in a high-risk population: should the diagnostic work-up include bronchodilator reversibility testing?

BACKGROUND

Underdiagnosis of chronic obstructive pulmonary disease (COPD) is widespread. Early detection of COPD may improve the outcome by timely smoking cessation, a change in lifestyle, and treatment with an inhaled bronchodilator (BD). The objective of this study was to evaluate the diagnostic role of BD reversibility testing in early COPD case finding.

METHODS

General practitioners (n=241) consecutively recruited subjects aged ≥35 years with relevant exposure (history of smoking, and/or occupational exposure) and at least one respiratory symptom. Information on age, smoking status, body mass index, dyspnea score (Medical Research Council scale), and spirometry was obtained. Individuals with airway obstruction (forced expiratory volume in one second [FEV1]/forced vital capacity [FVC] <0.70) underwent a BD test with an inhaled β2 agonist, which was considered positive if ΔFEV1 was >0.20 L and >12%. Asthma and COPD were, respectively, defined as an FEV1 increase >0.50 L and a post-BD FEV1/FVC <0.70.

RESULTS

In total, 4,049 subjects (51% male) were included (mean age 58 years, body mass index 27, 32 pack-years of smoking). A significant BD response was found in 143 (15%) of the 937 subjects (23%) with airway obstruction at screening spirometry. In 59% of these subjects, the post-BD FEV1/FVC remained <0.70. In 24% of the subjects with pre-BD airway obstruction, the post-BD FEV1/FVC ratio was within the reference range. In subjects with confirmed COPD, the mean increase in FEV1 following BD was 0.11 L±0.10 L. The subjects with COPD and a significant BD response were characterized by a higher prevalence of dyspnea (72% versus 57%, P=0.02) but less cough (55% versus 75%, P=0.001) when compared with COPD subjects without BD reversibility.

CONCLUSION

Administration of a BD in COPD case finding is important in order to determine the post-BD FEV1/FVC ratio. Exclusion of subjects with a significant BD response may result in underdiagnosis of COPD, and we question the need for the BD reversibility test in the diagnostic screening algorithm in early COPD case finding.