Depressive and anxiety symptoms in COPD: associations with diffusion impairment and echocardiographic pulmonary hemodynamic burden

BACKGROUND: Psychological distress is common yet often underrecognized in chronic obstructive pulmonary disease (COPD). Physiological correlates beyond spirometry may support biopsychosocial assessment in routine care, but their relation to depressive and anxiety symptoms remain insufficiently characterized. METHODS: In this single-center cross-sectional study, 56 clinically stable Japanese COPD outpatients (mean age 73 years; 87.5% men) completed the Self-Rating Depression Scale (SDS) and the State-Trait Anxiety Inventory (STAI). Clinical assessments included spirometry, %DLCO/VA, echocardiographic tricuspid regurgitation pressure gradient (TRPG), body mass index (BMI), and blood biomarkers. Associations were examined using Spearman's rank correlation and multivariable linear regression adjusted for age, sex, and BMI; Model 1 included %DLCO/VA and Model 2 included TRPG. Bootstrap resampling was used to assess the stability of key regression coefficients. RESULTS: Depressive symptoms (SDS ≥ 40) were present in 46.5% of the patients (severe 5.4%), and elevated state anxiety in 41.1% (severe 12.5%). SDS scores were correlated with lower %DLCO/VA, higher TRPG, and lower BMI. STAI-state scores were correlated with higher TRPG. In adjusted analyses, lower %DLCO/VA was independently associated with higher SDS scores, whereas higher TRPG was independently associated with higher SDS and STAI-state scores. %FEV1 was not associated with SDS or STAI scores. CONCLUSIONS: In this Japanese outpatient COPD cohort, depressive and anxiety symptoms were common. Elevated TRPG showed a more consistent association with psychological symptoms in bootstrap analyses, whereas lower %DLCO/VA was associated with depressive symptoms but showed less stable bootstrap support than the TRPG findings. These findings support an integrated biopsychosocial assessment approach to routine COPD care, incorporating physiological information beyond spirometric airflow measures.