Obstructive sleep apnea-COPD overlap syndrome common, linked with poor outcomes

Obstructive sleep apnea and COPD overlap syndrome is common and is associated with worse outcomes, poorer quality of life and a higher prevalence of comorbidities such as diabetes and hypertension compared with COPD only, researchers reported.

“Our study suggests that OSA is common in patients with COPD in pulmonary outpatient clinics, and pulmonologists should ... consider screening for OSA symptoms in these patients,” Pan Zhang, MD, from the department of control and prevention of chronic noncommunicable diseases at Xuzhou Center for Disease Control and Prevention in Jiangsu, China, and colleagues wrote in BMC Pulmonary Medicine.

The cross-sectional study included 842 patients with COPD (mean age, 63 years; 28% women) in the Xuzhou area in eastern China who were treated from December 2018 to December 2019. Researchers evaluated the modified Medical Research Council (MRC) Dyspnea Scale, Epworth Sleepiness Scale, COPD Assessment Test, Hospital Anxiety and Depression Scale, Charlson Comorbidity Index and STOP-Bang questionnaire for all patients and performed spirometry and overnight polysomnography.

In total, 66% of patients had obstructive sleep apnea, which was defined as apnea-hypopnea index of five or more events per hour.

The following factors were all significantly higher among patients with OSA-COPD overlap compared with patients with COPD alone:

• BMI;
• neck circumference;
• Epworth Sleepiness Scale score;
• COPD Assessment Test score;
• Charlson Comorbidity Index;
• Hospital Anxiety and Depression Scale score;
• STOP-Bang questionnaire;
• FEV₁ and FEV₁ percent predicted;
• FEV₁/FVC ratio; and
• prevlanece of hypertension, coronary heart disease and diabetes.

The prevalence of severe COPD was significantly lower in patients with OSA-COPD overlap. Patients with severe COPD had a lower OSA risk compared with patients with mild or moderate COPD (OR = 0.632; 95% CI, 0.4-0.99; P = .048).

The researchers identified BMI, neck circumference, Epworth Sleepiness Scale, COPD Assessment Test, Charlson Comorbidity Index, Hospital Anxiety and Depression Scale, hypertension and diabetes as independent risk factors for OSA-COPD overlap syndrome (P < .05 for all).

The researchers reported no significant differences for age, sex ratio, modified MRC Dyspnea Scale, smoking index, number of acute exacerbations and hospitalizations in the past 12 months and prevalence of cor pulmonale between patients with and without risk for OSA symptoms (P > .05 for all).