Background: Sleep problems associated with chronic obstructive pulmonary disease may have an important impact on quality of life and health outcome measures in patients. The aim of this study was to prospectively assess differences in symptom profile and polysomnographic parameters in patients with stable mild to moderate COPD and age, gender, and body-mass-index matched controls without airflow obstruction.
Methods: The Sleep Disorders Questionnaire was administered to both patients and controls prior to clinical and polysomnographic evaluation. Responses obtained from the questionnaire were used to construct four independent symptom scales: sleep apnea, periodic limb movement syndrome, psychiatric sleep disorder, and narcolepsy. Associations between each diagnostic scale and sleep parameters were considered by means of multiple analyses of covariance.
Results: Fifty-two patients with mild-to-moderate COPD (age 62±8 years, BMI 29±7 kg/sqm) and 52 age, gender, and body-weight matched controls without COPD were studied. Patients with COPD had overall lower sleep efficiency, a lower total sleep time, and lower mean overnight oxygen saturation compared to controls. Patients with COPD were significantly more likely to report symptoms such as insomnia and difficulty in initiating and maintaining sleep, resulting in overall higher psychiatric sleep disorder scale scores in patients compared with controls. Minimum oxygen saturation was an independent predictor for all symptom scales. After correcting for potentially confounding factors, including pack/years of smoking, total sleep time, sleep efficiency, arousal index, mean and minimum oxygen saturation, and apnea-hypopnea-index, the between group-differences for both the periodic limb movement and psychiatric sleep disorder scale scores remained statistically significant.
Conclusions: We observed significant differences in both quantity and quality of sleep between patients with stable mild to moderate chronic obstructive pulmonary disease and respective controls.
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