Disturbed sleep among COPD patients is longitudinally associated with mortality and adverse COPD outcomes

Objective: To investigate the cross-sectional association between COPD severity and disturbed sleep and the longitudinal association between disturbed sleep and poor health outcomes. Methods: Ninety eight adults with spirometrically-confirmed COPD were recruited through population-based, random-digit telephone dialing. Sleep disturbance was evaluated using a 4-item scale assessing insomnia symptoms as: difficulty falling asleep, nocturnal awakening, morning tiredness, and sleep duration adequacy. COPD severity was quantified by: FEV1 and COPD Severity Score, which incorporates COPD symptoms, requirement for COPD medications and oxygen, and hospital-based utilization. Subjects were assessed one year after baseline to determine longitudinal COPD exacerbations and emergency utilization and were followed for a median 2.4 years to assess all-cause mortality. Results: Sleep disturbance was cross-sectionally associated with cough, dyspnea, and COPD Severity Score, but not FEV1. In multivariable logistic regression, controlling for sociodemographics and body-mass index, sleep disturbance longitudinally predicted both incident COPD exacerbations (OR = 4.7; p = 0.018) and respiratory-related emergency utilization (OR = 11.5; p = 0.004). In Cox proportional hazards analysis, controlling for the same covariates, sleep disturbance predicted poorer survival (HR = 5.0; p = 0.013). For all outcomes, these relationships persisted after also controlling for baseline FEV1 and COPD Severity Score. Conclusions: Disturbed sleep is cross-sectionally associated with worse COPD and is longitudinally predictive of COPD exacerbations, emergency health care utilization, and mortality. (C) 2012 Elsevier B. V. All rights reserved.