Depression is a major determinant of both disease-specific and generic health-related quality of life in patients with severe COPD

Abstract

Background: Patients with COPD experience significant impairment in their quality of life as disease progresses; those with severe COPD are most affected. The aim of this study was to identify the predictors of disease-specific and generic health-related quality of life in patients with severe COPD. Methods: This was a multicentre prospective cross-sectional study of 80 patients with severe COPD. At enrolment, all patients completed the disease-specific instrument (St George's Respiratory Questionnaire; SGRQ), and the generic instrument (Short Form 36 Health Survey Questionnaire; SF-36). Data were analysed with Pearson's correlation and multiple linear regression. Findings: The mean age of the patients was 66±8 years; 93% were men, and the mean post-bronchodilator forced expiratory volume in 1 sec (FEV1) was 38% predicted. SGRQ and SF-36 scores were not influenced by age or sex. Depression, dyspnoea, number of exacerbations, and exercise capacity significantly predicted SGRQ total score, explaining 56.8% of the variance in multiple linear regression (p<0.05). Depression was the strongest determinant of SGRQ total scores. SF-36 physical component summary scores were related to depression, dyspnoea, and number of exacerbations, explaining 46.2% of the variance in a multiple linear regression (p<0.05). SF-36 mental component summary scores were related to depression and anxiety, explaining 47.4% of the variance in a multiple linear regression (p<0.05). Interpretation: Depression was a significant determinant of both disease-specific and generic health-related quality of life in patients with severe COPD. Clinicians should pay attention to a number of physiological and psychosocial factors to optimise health-related quality of life in patients with severe COPD.