Whether there are increased rates of chronic diseases associated with the combination of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) overlap syndrome (OVS) has not been determined. The purpose of this study was to assess the prevalence of five comorbidities in COPD and OVS patients. A total of 968 patients with confirmed COPD were included in this study. Participants were requested to fill out a questionnaire involving their basic information and medical history. All subjects underwent one overnight polysomnography and were then divided into an OVS group or a COPD only group according to their apnea-hypopnea index. The prevalence of hypertension, diabetes, cardiovascular disease, arrhythmia and cerebrovascular disease were compared and risk factors for comorbidities in COPD patients were identified. Compared with the COPD only group, the prevalence of hypertension was significantly higher in the OVS group, however, the prevalence rates of the other four kinds of diseases were not statistically different between the two groups. In COPD patients, the prevalence of hypertension increased with the severity of OSA and the prevalence of arrhythmia increased with airflow limitation severity. Risk factors for OSA in patients with COPD included BMI, FEV1%, Epworth Sleepiness Scale score and the Sleep Apnea Clinical Score. OSA was an independent risk factor for hypertension. The other risk factors for hypertension in COPD patients included age, BMI, CAT score and alcohol consumption. Age, lower FEV1% may be risk factors for arrhythmia. OVS patients were associated with a high prevalence rate of hypertension, while OSA was an independent risk factor for hypertension.
Keywords: Chronic obstructive pulmonary disease; arrhythmia; comorbidity; hypertension; obstructive sleep apnea; overlap syndrome.