Relationship between degree of dyspnoea and health-related quality of life in patients with chronic obstructive pulmonary disease

Abstract

Dyspnoea is a characteristic symptom of chronic obstructive pulmonary disease (COPD), which impairs everyday functioning of patients. The aim of our study was to evaluate the relationship between the degree of dyspnoea of COPD patients and their health-related quality of life. We measured the degree of dyspnoea and health-related quality of life in 85 COPD outpatients (46 male; mean age was 58 +/- 12 years; mean forced expiratory volume in one second (FEV,) was 47.9 +/- 18.6% predicted). The degree of dyspnoea was assessed by Baseline Dyspnoea Index (BDI), List of Daily Activities (DAL), Visual Analogue Scale (VAS), Modified MRC Dyspnoea Scale, and Borg Category Scale (BCS). The patients filled two standardized questionnaires for measuring health-related quality of life: the generic one--15D, and the respiratory specific one--the St. George's Respiratory Questionnaire (SGRQ). Total 15D and SGRQ scores, as well as the scores for individual domains of SGRQ (symptoms, activity and impact scores) for each patient were calculated. In 40 out of 85 patients, the same procedure was repeated at the follow-up, with a mean 4-week interval between the visits. There were statistically highly significant correlations (p < 0.01) between values of all dyspnoea scale scores evaluated and all the health-related quality of life scores. The highest degree of correlation of both total SGRQ and 15D scores was found for the values of BCS (r = 0.731 and -0.776, respectively). A statistically significant correlation between the changes of all SGRQ (but not 15D) scores and all dyspnoea score changes (except for MRC) were also recorded. The degree of dyspnoea of COPD outpatients that could be well-determined by the scales used in our study clearly reflects the impairment of their health-related quality of life as assessed by the instruments used. All of the questionnaires we used in this study have good measurement properties for their purposes.