Sleep Duration and Its Associations with Mortality and Quality of Life in Chronic Obstructive Pulmonary Disease: Results from the 2007–2015 KNAHNES

Abstract

<b><i>Background:</i></b> While extreme sleep duration negatively affects mortality and health-related quality of life (HRQOL) in general populations, the relationship remains uncertain in patients with chronic obstructive pulmonary disease (COPD). <b><i>Objectives:</i></b> To evaluate the association between sleep duration and mortality and HRQOL in patients with COPD. <b><i>Methods:</i></b> We analyzed 3,349 participants with COPD enrolled in the 2007–2015 Korea National Health and Nutrition Examination Survey (KNHANES). Participants aged 40 years or older with a smoking history and prebronchodilator forced expiratory volume in 1 s/forced vital capacity (FEV₁/FVC) &#x3c;0.7 were eligible. The participants were categorized as short sleepers (&#x3c;6 h), 6–8 h, and long sleepers (&#x3e;8) according to self-reported sleep duration. The outcome variables were all-cause mortality and HRQOL. HRQOL was measured using the European Quality of Life-5 Dimensions (EQ-5D) index. <b><i>Results:</i></b> During a median of 6.5 years, 386 (11.5%) participants died. In unadjusted Cox regression analysis, short sleepers with COPD had an increased risk of death (hazard ratio, 1.35; 95% confidence interval [CI]: 1.07–1.71). However, this association was not significant after adjusting for sociodemographic factors, BMI, FEV₁, and comorbidities. In unadjusted and adjusted multiple linear regression, short sleepers had significantly worse HRQOL. The adjusted means of the EQ-5D index were 0.88 (95% CI: 0.87–0.89) for short sleepers, 0.90 (95% CI: 0.90–0.91) for 6- to 8-h sleepers, and 0.89 (95% CI: 0.87–0.91) for long sleepers (<i>p</i> = 0.01). <b><i>Conclusions:</i></b> In patients with COPD, sleep duration was not associated with all-cause mortality. However, short sleep duration was significantly associated with worse HRQOL.