Sleep quality predicts quality of life in chronic obstructive pulmonary disease

PURPOSE Chronic obstructive pulmonary disease (COPD) patients may suffer from poor sleep and health-related quality of life. We hypothesized that disturbed sleep in COPD is correlated with quality of life. METHODS In 180 patients with COPD (forced expired volume in 1 second [FEV(1)] 47.6 ± 15.2% predicted, 77.8% male, aged 65.9 ± 11.7 years), we administered general (Health Utilities Index 3) and disease-specific (St George's Respiratory) questionnaires and an index of disturbed sleep (Pittsburgh Sleep Quality Index). RESULTS Overall scores indicated poor general (Health Utilities Index 3: 0.52 ± 0.38), disease- specific (St George's: 57.0 ± 21.3) quality of life and poor sleep quality (Pittsburgh 11.0 ± 5.4). Sleep time correlated with the number of respiratory and anxiety symptoms reported at night. Seventy-seven percent of the patients had Pittsburg scores >5, and the median Pittsburgh score was 12. On multivariate regression, the Pittsburgh Sleep Quality Index was an independent predictor of both the Health Utilities Index 3 and the St George's scores, accounting for 3% and 5%, respectively, of the scores. Only approximately 25% of the patients demonstrated excessive sleepiness (Epworth Sleepiness Scale >9). CONCLUSIONS Most patients with COPD suffer disturbed sleep. Sleep quality was correlated with general and disease-specific quality of life. Only a minority of COPD patients complain of being sleepy.