B24-13 Impact of Emphysema on Lung Function Improvement With Triple Therapy in COPD: A Longitudinal Mixed-effects Model Analysis

Background The coexistence of emphysema is a key computed tomography (CT) phenotype in chronic obstructive pulmonary disease (COPD). Its influence on the response to triple therapy (ICS/LAMA/LABA) remains inadequately investigated. This study aimed to determine whether the presence of emphysema affects improvement in lung function among patients with COPD receiving triple therapy. Methods This retrospective study was conducted in 118 patients with COPD receiving triple therapy. Inclusion criteria comprised the availability of a chest CT scan, baseline spirometry, and follow-up data after treatment initiation. Individuals with any history of asthma were excluded. Patients were stratified by the presence (n = 81) or absence (n = 37) of emphysema on imaging. The outcomes were changes in spirometry parameters. The analysis used linear mixed-effects models that included the interaction between emphysema status and a quadratic polynomial of time (in years). Models were additionally adjusted for baseline covariates (Model 1: BMI, baseline FEV1/FVC, GOLD stage, age, sex, medication, smoking status, bronchodilator response), and further adjusted for disease progression by including a baseline-by-time interaction (Model 2) to minimize the impact of possible confounding factors. Results At baseline, the emphysema group was older, comprised a higher proportion of males, and had a lower FEV1/FVC. Follow-up data were collected after a median duration of 161 days (interquartile range: 254 days). In Model 2, emphysema was a significant independent predictor of poorer FEV1/FVC improvement (β = -1.867, P = 0.019), while the interaction between emphysema and time was not statistically significant. To quantify the treatment response, changes in lung function after one year were calculated. Among patients with emphysema, the improvements in FEV1/FVC and FEV1 failed to reach statistical significance, as the 95% confidence intervals included zero. Moreover, when compared directly to the non-emphysema group, the emphysema group exhibited a significantly smaller improvement in FEV1/FVC (-3.47%, P = 0.023) and FEV1/FVC percent predicted (-4.18%, P = 0.037). Conclusion The CT-based emphysema phenotype is associated with a diminished lung function response to triple therapy in COPD, thus highlighting its potential clinical value for prognostic stratification and personalized medicine.