A combined bronchodilator response (BDR) in patients with chronic obstructive pulmonary disease (COPD) is associated with less emphysema and lower mortality, but a greater frequency of exacerbations, according to study results published in the Annals of the American Thoracic Society.
Bronchodilator responses, defined as an increase in prebronchodilator forced expiratory volume in 1 second (FEV1) and/or forced vital capacity (FVC) ≥12% and ≥200 mL after bronchodilator administration in patients with COPD were retroactively analyzed from the COPDGene study. A modified American Thoracic Society (ATS) Respiratory Epidemiology questionnaire, 6-minute walk test (6-MWT) results, and pre- and post-bronchodilator spirometry were used to determine functional impairment. Patients were contacted every 6 months to complete a validated questionnaire regarding COPD exacerbations and were categorized into 4 groups based on BDR category: no-BDR, FEV1-BDR, FVC-BDR, and combined-BDR and compared.
Of the 4458 patients with COPD screened for study inclusion, 3340 were included in the analysis. Patients who self-reported asthma were excluded from the study. Follow-up data for exacerbations and vital status were available in 2980 and 2972 participants, respectively. In the whole cohort, 1083 patients (32.43%) had ATS-BDR. Of those patients, 182 (5.45%) had FEV1-BDR, 522 (15.63%) had FVC-BDR, and 379 (11.34%) had combined-BDR.
Compared with patients with no BDR, FEV1-BDR patients were younger, had less advanced COPD stage, less computed tomography (CT) emphysema and CT gas trapping, less functional small airways disease, and covered a longer 6-MWT distance. Compared with no-BDR, FVC-BDR patients were older, had greater dyspnea, greater gas trapping, greater functional small airway disease, and covered a shorter 6-MWT distance. Compared with no-BDR, the combined-BDR group reported a higher frequency of chronic bronchitis, had no difference in CT emphysema and gas trapping, but had more functional small airway disease and covered a greater 6-MWT distance. In addition, having combined-BDR was associated with lower mortality (hazard ratio, 0.76; 95% CI, 0.58-0.99; P =.046)
“Combined-BDR is associated with less emphysema and lower mortality, but with greater frequency of exacerbations, indicating a putative COPD phenotype with asthma-like characteristics,” the researchers wrote. “More research is needed to test whether the combined-BDR phenotype helps identify patients with the asthma-COPD overlap, and whether targeting patients with this phenotype will result in improved outcomes.”
Disclosures: The COPDGene project is partially funded by an advisory board that includes the following pharmaceutical companies: AstraZeneca, Boehringer Ingelheim, GlaxoSmithKline, Novartis, Pfizer, and Siemens and Sunovion.
Fortis S, Comellas A, Make BJ, et al. Combined FEV1 and FVC bronchodilator response, exacerbations, and mortality in COPD [published March 25, 2019]. Ann Am Thorac Soc. doi:10.1513/AnnalsATS.201809-601OC