Objective: COPD patients frequently complain of symptoms such as dyspnoea and leg fatigue during exercise. However, the impact of these symptoms on the health-related quality of life (HRQoL) is not known. This study tested whether dyspnoea and leg fatigue during exercise affects the HRQoL of patients with COPD.
Methods: In a cross-sectional study, 90 patients with stable COPD (mean age, 76.0+/-0.7 years; FEV(1), 1.11+/-0.04 L) completed the St. George's Respiratory Questionnaire (SGRQ), pulmonary function testing, arterial blood gas analysis, and a 6-min walking distance test (6MWD). Dyspnoea and leg fatigue during exercise were quantitated into 12 grades using the Borg scale (0--10). Correlations between the SGRQ and various variables were determined. In a longitudinal study, 22 patients with COPD (mean age, 71.5+/-1.1 years; FEV(1), 1.31+/-0.08 L) completed a pulmonary rehabilitation program, for which correlations between changes in the SGRQ as well as changes in both dyspnoea and leg fatigue, during the 6MWD before and 3 months after pulmonary rehabilitation, were examined.
Results: For the cross-sectional study, the total SGRQ score correlated significantly with the walking distance, dyspnoea and leg fatigue during the 6MWD and FEV(1), respectively. Stepwise multiple regression analysis showed that dyspnoea and leg fatigue during the 6MWD were independent variables for HRQoL measured by the SGRQ. For the longitudinal study, changes in the SGRQ correlated significantly with changes in dyspnoea and leg fatigue, before and 3 months after, pulmonary rehabilitation.
Conclusions: Symptoms, such as the degree of dyspnoea and leg fatigue during exercise, are significant variables which influence the HRQoL of patients with COPD. In addition, the improvement in HRQoL following pulmonary rehabilitation may be due to improvements in dyspnoea and leg fatigue in patients with COPD.