Fatigue a Potential Indicator of Overlapping Sleep Apnea and COPD

Patients with overlapping chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) are significantly more fatigued than patients with OSA alone, according to research published in PLOS One.

Researchers evaluated sleepiness, fatigue, anxiety, and depression among patients with overlap syndrome, OSA, and a control group. On the basis of the findings, researchers recommended that “[f]atigue should be evaluated whenever there is clinical suspicion of overlap syndrome.”

The case-control study enrolled 38 patients with overlap syndrome, 38 patients with OSA only, and 28 healthy control patients through the Alexandra Hospital of Athens. The patients underwent pulmonary function tests, oximetry, and overnight polysomnography and completed the Epworth Sleepiness Scale, Fatigue Severity Scale, and Hospital Anxiety and Depression Scale before and after a 3-month treatment with continuous positive airway pressure (CPAP). The 2 patient groups exhibited similar comorbidities and arterial blood pressure values and were comparable in age and body mass index and neck, waist, and hip circumferences.

The limitations of the study included the limited sample size, the heterogeneous nature of prognosis and clinical outcomes for COPD and OSA, the assessment of CPAP adherence based on algorithms of 2 types of machines, not measuring markers of inflammation, and not recording sleep habits and duration.

The data collected showed that 2 groups differed significantly in pulmonary function tests and in daytime oximetry, but the Epworth Sleepiness Scale, Hospital Anxiety and Depression Scale-Anxiety scores, and Hospital Anxiety and Depression Scale-Depression scores were not significantly different. Even after 3 months of CPAP therapy, patients with overlap syndrome showed significantly more fatigue than patients with OSA only.

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The findings suggest that sleepiness cannot be used to distinguish the 2 groups and that CPAP can partially reverse an increased propensity for sleep. Poor sleep quality is likely one of several determinants of sleepiness. Factors such as age, obesity, diabetes, insulin resistance, physical activity, depression, and endogenous genetic characteristics may add to the expression of sleepiness in patients and healthy subjects alike.


Economou N-T, Ilias I, Velentza L, Papachatzakis Y, Zarogoulidis P, Kallianos A, et al. Sleepiness, fatigue, anxiety and depression in chronic obstructive pulmonary disease and obstructive sleep apnea – overlap – syndrome, before and after continuous positive airways pressure therapy. PLoS ONE. 2018;13(6):e0197342.