Disease severity and health perception as independent predictors of anxiety and depression in chronic obstructive pulmonary disease: A multivariable regression analysis

Background: Anxiety and depression are significant psychiatric comorbidities in chronic obstructive pulmonary disease (COPD), yet the mechanisms through which disease severity and health perception influence psychiatric outcomes remain incompletely characterized. Aim: To examine whether disease severity (BODE index) and subjective health perception (COPD Assessment Test [CAT]) independently predict anxiety and depression in COPD, and whether sociodemographic factors operate through these disease-related pathways. Materials and Methods: A cross-sectional study of 103 COPD patients (mean age 63.73 years, 74.8% male) was conducted at a tertiary care center in Eastern India. Participants completed the Generalized Anxiety Disorder-7 (GAD-7), Patient Health Questionnaire-9 (PHQ-9), and CAT. Disease severity was assessed using the BODE index and GOLD staging. Multivariate regression analyses identified independent predictors of anxiety and depression while controlling for age, gender, and smoking history (pack-years). Results: The BODE index was the strongest independent predictor of both anxiety (standardized β = 0.68, P < 0.001; R ² = 0.69) and depression (standardized β = 0.55, P < 0.001; R ² = 0.47). The CAT score independently predicted anxiety (standardized β = 0.23, P < 0.01) but not depression, indicating that subjective health perception uniquely contributes to anxiety beyond objective disease severity. Importantly, gender, age, and smoking history showed significant bivariate associations with psychiatric symptoms but became non-significant in multivariable models, indicating these sociodemographic effects are mediated through disease severity and health perception rather than representing independent demographic risk factors. The differential associations with anxiety versus depression suggest anxiety is predominantly physiologically driven through dyspnea and threat appraisal, whereas depression involves additional psychosocial determinants. Conclusion: Psychiatric morbidity in COPD operates through integrated physiological, perceptual, and psychological pathways, with disease severity and subjective health perception as primary independent predictors. The distinct mechanisms underlying anxiety versus depression suggest that differentiated, mechanism-based interventions—targeting dyspnea management and catastrophic thinking for anxiety and integrated psychosocial rehabilitation for depression—may optimize clinical outcomes. Prospective longitudinal studies are warranted to establish causal pathways and test whether targeting these mechanisms reduces psychiatric morbidity in COPD.