Actigraphic assessment of sleep in chronic obstructive pulmonary disease

Previously, sleep in chronic obstructive pulmonary disease (COPD) has been objectively investigated only by lab-based polysomnography. The main purpose of this study was to evaluate sleep quality in COPD patients in their home environment using actigraphy. We also investigated the factors associated with sleep impairment and the relationship between objective and subjective sleep quality and daytime somnolence in these patients.

Twenty-six patients with moderate to very severe COPD and 15 controls were studied by actigraphy for at least 5 days. Subjective sleep quality was evaluated by the Pittsburgh Sleep Quality Index and daytime sleepiness by the Epworth Sleepiness Scale (ESS). Dyspnea was quantified by the modified Medical Research Council (MMRC) scale.

COPD patients showed increased sleep latency (p = 0.003), mean activity (p = 0.003), and wake after sleep onset (p = 0.003) and reduced total sleep time (TST; p = 0.024) and sleep efficiency (p = 0.001), as compared to controls. In patients, severity of dyspnea was correlated with sleep activity (r = 0.41; p = 0.04) and TST (r = -0.46; p = 0.02) and multiple regression analysis showed that MMRC score was the best predictor of TST (p = 0.02) and sleep efficiency (p = 0.03). Actigraphy measures during daytime were not significantly different between patients and controls. Subjective sleep quality was poorer in patients than controls (p = 0.043). ESS scores were not significantly different between the two groups. Actigraphy measures were not correlated with subjective sleep quality or daytime somnolence in both groups.

Nocturnal sleep is markedly impaired in stable COPD patients studied by actigraphy in their home environment and this impairment is related to severity of dyspnea.