Sleep disturbance is a common symptom in patients with COPD and there are significant differences between the sleep disorders in patients with COPD and those encountered in the general population. Some of these variations are: Less amount of rapid eye movement (REM) sleep and frequent arousals during periods of desaturation are often noted in patients with COPD[1]. Patients with COPD also become more hypoxemic during sleep than when awake and the hypoxemia during sleep is even greater than that encountered during exercise[2].
The main cause of hypoxemia during REM sleep could be given by Hypoventilation and there may be additional contributions from ventilation perfusion mismatches and reductions in functional residual capacity according with Ballard, et al (1995). In recent times, researchers have reported that quality of sleep is one of the major determinants of quality of life in patients with Chronic obstructive pulmonary disease and that it could predict a poor rate of survival in them. Based on that, a group of researchers from the University College of Medicine and the Department of Critical Care of The Memorial Hospital in Taiwan developed this investigation with the following aim, methods and results.
Aim: identify the factors associated with sleep disturbance in patients with COPD. Methods: The study was a retrospective, observational, and multicenter research. Data including age, sex, body mass index, smoking status, COPD inhaler prescribed, clinical symptoms, pulmonary function tests, medical history of comorbidities, and questionnaires were collected. Parameters including demographics, symptoms, medication, severity, functional classification, and comorbidities were correlated with sleep quality scores.
Results: Among 377 patients with COPD, 200 (53 %) patients experienced poor sleep quality (Pittsburg Sleep Quality Index scores > 5). A significant difference in sleep quality, as measured by PSQI scores, was noted between groups based on the 2011 Global Initiatives for Chronic Obstructive Lung Disease (GOLD) classification system. The most common sleep disturbances included “getting up to use the bathroom” (70.3 %), “wake up at night or early morning” (40.3 %), and “cough and snore loudly at night” (15.9 %). The use of inhaled corticosteroids, the presence of wheezing, COPD Assessment Test (CAT) scores, and Modified Medical Research Council (mMRC) dyspnea scale scores positively correlated with poor sleep quality (odds ratio: 1.51, 1.66, 1.09, and 1.30, respectively). Upon multivariate analysis, the CAT score was an independent factor for poor sleep quality in these patients. With the exception of sleep problem items, based on the CAT questionnaire, phlegm was significantly higher in COPD patients with poor sleep quality.
Conclusions: More than half of our patients with COPD experienced poor sleep quality. The most common sleep complaints included getting up for the bathroom, waking up at night or in the early morning, and coughing or snoring loudly. Symptoms including wheezing, phlegm, and the use of inhaled corticosteroid may also have contributed to poor sleep quality in these COPD patients.
References:
[1] Fleetham J, West P, Mezon B, Conway W, Roth T, Kryger M. Sleep, arousals, and oxygen desaturation in chronic obstructive pulmonary disease. The effect of oxygen therapy. Am Rev Respir Dis. 1982;126(3):429–33.
[2] Mulloy E, McNicholas WT. Ventilation and gas exchange during sleep and exercise in severe COPD. Chest. 1996;109(2):387–94.
