Factors affecting the relationship between psychological status and quality of life in COPD patients

Abstract

Background: This study aims to (i) evaluate the association between anxiety and depressive symptoms and health-related quality of life (HRQoL); and (ii) identify the effect modifiers of this relationship in patients with chronic obstructive pulmonary disease (COPD).

Methods: A total of 337 clinically stable COPD patients answered the St. George's Respiratory Questionnaire (SGRQ) (assessing HRQoL) and the Hospital Anxiety and Depression Scale (HADS). Socio-demographic information, lung function, and other clinical data were collected.

Results: Most patients (93%) were male; they had a mean (SD) age of 68 (9) years and mild to very severe COPD (post-bronchodilator FEV1 52 (16)% predicted). Multivariate analyses showed that anxiety, depression, or both conditions were associated with poor HRQoL (for all SGRQ domains). The association between anxiety and total HRQoL score was 6.7 points higher (indicating a worse HRQoL) in current workers than in retired individuals. Estimates for patients with "both anxiety and depression" were 5.8 points lower in stage I-II than in stage III-IV COPD, and 10.2 points higher in patients with other comorbidities than in those with only COPD.

Conclusions: This study shows a significant association between anxiety, depression, or both conditions and impaired HRQoL. Clinically relevant factors affecting the magnitude of this association include work status, COPD severity, and the presence of comorbidities.

Figure 1

Association between psychological status and health-related quality of life in 337 stable COPD patients according to working status (a), COPD severity (b), and comorbidities (c). Multivariate models adjusted by covariates in Table 3. The dots represent the regression coefficients and the vertical bars indicate the 95% confidence intervals. These estimates are interpreted as the change in SGRQ score (points) with respect to the reference group (subjects with neither anxiety nor depression (horizontal line)). Subjects with depression only were not included due to small sample size. † Chronic diseases from the Charlson index. One: only COPD; two or more: one or more in addition to COPD.