Prevalence and clinical significance of pre- and post-bronchodilator airflow obstruction in COPD patients

Abstract

Background: Chronic obstructive pulmonary disease (COPD) is a progressive respiratory disorder characterized by persistent airflow limitation. This study investigates the prevalence and clinical significance of prebronchodilator (PREO) and post-bronchodilator (POSTO) airflow obstruction in COPD. Methods: This retrospective cohort study analyzed data from 3252 COPD patients aged >= 40 years, registered from January 2012 to December 2019 at 54 medical centers in South Korea. Patients were categorized into three groups: PREO & post-bronchodilator non-obstruction (POSTN), pre-bronchodilator non-obstruction (PREN) & POSTO, and PREO & POSTO. The primary outcome was moderate-to-severe exacerbation over 3 years. Secondary outcomes included GOLD group progression and rapid FEV, decline. Results: The majority of patients (96.2 %) were in the PREO & POSTO group, with smaller proportions in the PREO & POSTN (2.8 %) and PREN & POSTO (1.0 %) groups. During the 3-year observation, 21.6 % of patients experienced moderate-to-severe exacerbations, 6.2 % exhibited GOLD group progression, and 20.0 % showed rapid FEV, decline. The PREO & POSTO group had a higher risk of exacerbations compared to the PREO & POSTN group (odds ratio = 8.33 [95 % CI = 1.53-45.4], P-value = 0.014), but this was not statistically significant in multivariable analysis. Post-bronchodilator spirometry patterns did not significantly impact GOLD group progression or FEV, decline. Conclusion: PREO & POSTO was common among COPD patients, while isolated PREO & POSTN was rare, supporting pre-bronchodilator spirometry as a screening tool. Although patients with PREO & POSTO showed higher exacerbation risks in univariable analysis, statistical significance disappeared after adjustment. GOLD group progression or FEV, decline did not significantly differ by post-bronchodilator spirometry patterns.