Obstructive sleep apnea tied to poor outcomes in COPD patients: BMC

China: In a new study, it was found that overlap syndrome patients exhibited a worse quality of life, greater daily drowsiness, and a higher prevalence of hypertension and diabetes than chronic obstructive pulmonary disease (COPD) patients alone. This study was conducted by Pan Zhang and the team, the results of which were published in BMC Pulmonary Medicine.

The term "overlap syndrome" refers to the combination of obstructive sleep apnea (OSA) and COPD, which has worse results than either illness alone. The purpose of this study was to determine the prevalence and potential determinants of overlap syndrome, as well as its relationship to clinical outcomes in COPD patients.

For this study, researchers assessed the modified Medical Research Council dyspnea scale (mMRC), Epworth sleepiness scale (ESS), COPD assessment test (CAT), Hospital Anxiety and Depression Scale (HADS), Charlson Comorbidity Index (CCI), and STOP-Bang questionnaire (SBQ) in all patients, as well as spirometry and full overnight polysomnography. OSA was defined as an apnea-hypopnea index (AHI) of 5 occurrences per hour. Univariate and multivariate logistic regression analyses were used to identify risk variables for OSA in COPD patients.

The key findings of this study were as follow:

1. An AHI of 5 occurrences per hour was seen in 556 individuals (66%).

2. There were no significant differences between the two groups in terms of age, sex ratio, mMRC score, smoking index, number of acute exacerbations and hospitalizations in the previous year, or prevalence of cor pulmonale (all p > 0.05).

3. BMI, neck circumference, CAT score, CCI, ESS, HADS, and SBQ scores, forced expiratory volume (FEV)1, FEV1 percent pred, FEV1/forced vital capacity ratio, and the prevalence of hypertension, coronary heart disease, and diabetes were all significantly higher in the COPD-OSA group compared to the COPD group (p 0.05).

4. In COPD patients, BMI, neck circumference, ESS, CAT, CCI, HADS, hypertension, and diabetes were all independent risk factors for OSA.

5. SBQ might be utilized to test for OSA in COPD patients. When compared to individuals with mild or moderate COPD, people with severe COPD had a reduced incidence of OSA.

In conclusion, the findings of this study revealed that COPD patients with overlapping OSA had a worse quality of life, greater daytime drowsiness, and higher blood pressure than COPD patients without OSA. BMI, as well as CAT and ESS scores, were found to be independent risk factors for COPD aggravated by OSA. Patients with severe COPD, on the other hand, had a decreased incidence of OSA. Our findings imply that OSA is widespread in COPD patients in pulmonary outpatient clinics, and pulmonologists should consider screening these patients for OSA symptoms.

Reference:

Zhang, P., Chen, B., Lou, H. et al. Predictors and outcomes of obstructive sleep apnea in patients with chronic obstructive pulmonary disease in China. BMC Pulm Med 22, 16 (2022). https://doi.org/10.1186/s12890-021-01780-4