Clinical Outcomes in Patients With COPD With Disease Stability: Data from the Korea COPD Subgroup Study Cohort.

Abstract

COPD is a heterogeneous disease with progressive airflow limitation. Despite therapeutic advances, current treatments poorly halt COPD progression. Disease stability (DS) is a proposed treatment goal, but its clinical significance remains uncertain. What are the differences in lung function decline, exacerbation risk, and mortality between patients with COPD with and without DS? This study analyzed data from the Korean COPD Subgroup Study, a nationwide prospective cohort of patients with COPD in South Korea. Participants were ≥ 40 years of age and had a postbronchodilator FEV₁/FVC ratio < 0.70. Ten-year all-cause mortality data were obtained from national death records and merged with cohort data. DS (+) was defined as the absence of moderate-to-severe exacerbations, no decline in FEV₁, and no worsening of the St. George's Respiratory questionnaire score during the first year. Clinical outcomes were compared between patients with DS (+) and patients without DS (+), who were classified as DS (-). Among 1,639 patients analyzed, 147 (9.0%) achieved DS (+), whereas 1,492 (91.0%) were classified as DS (-). Baseline characteristics were similar between groups. Compared with the DS (-) group, the DS (+) group exhibited significantly lower rates of moderate-to-severe exacerbations (incidence rate ratio, 0.30; P = .033) and severe exacerbations (incidence rate ratio, 0.26; P = .002). Paradoxically, the annual decline in FEV₁ was greater in the DS (+) group (-45.8 vs -10.3 mL/y; P < .001). Multivariable Cox regression analysis demonstrated that DS (+) status was independently associated with a significantly reduced risk of all-cause mortality (adjusted hazard ratio, 0.56; P = .036). Patients with COPD with DS (+) showed reduced exacerbations and mortality. These findings support DS as a clinically meaningful and achievable treatment target in COPD, with potential utility in guiding personalized disease management.