Exploring health consequences of Asthma-COPD overlap syndrome in a national study

Asthma-COPD overlap syndrome (ACOS) represents a clinically significant yet under characterized respiratory phenotype. Comprehensive population-based assessments of ACOS-attributable burden, smoking dose-response relationships, phenotypic subtypes, and mechanistic pathways remain limited. Using 2023-2024 Behavioral Risk Factor Surveillance System data, we conducted 1:1 propensity score matching of 675 ACOS patients with controls without respiratory disease, balanced on 15 covariates including demographics, smoking exposure, BMI, and adverse childhood experiences. Outcomes encompassed health-related quality of life, functional disabilities, healthcare access, and health behaviors. Restricted cubic splines characterized smoking dose-response relationships. Latent class analysis identified ACOS phenotypes. Structural equation modeling with bootstrapping (5,000 resamples) quantified mediation pathways. Despite rigorous matching, ACOS conferred 4.6 additional physically unhealthy days monthly (Cohen’s d=0.37), 41% increased activity limitation risk (RR=1.41), and 19% elevated functional disability prevalence (RR=1.19). Smoking exhibited significant nonlinear dose-response (χ 2 =286.4, P