[Analysis of risk factors and consequences for concurrent obstructive sleep apnea in chronic obstructive pulmonary...

Objective: To compare clinical characteristics between patients with chronic obstructive pulmonary disease (COPD) and COPD -OSA overlap, and to analyze the risk factors for OSA in patients with COPD. Methods: A total of 431 patients with COPD were divided into a COPD-OSA group with AHI>15 events/h or a COPD group with AHI ≤ 15 events/h according to the results of polysomnography, and their clinical characteristics were summarized. Risk factors for OSA overlap in COPD patients were identified by univariate and multivariate logistic regression analyses. Results: There were no significant differences in gender composition, dyspnea scale (mMRC) score, the numbers of acute exacerbations and hospitalizations in the last year, prevalence of coronary heart disease, or cor pulmonale or diabetes mellitus in the two groups (all P>0.05). Age, BMI, neck circumference, smoking index, COPD assessment test (CAT) score, the values of FEV(1) or FEV(1)%, FEV(1)/FVC ratios, and the prevalence of hypertension in the COPD-OSA group with AHI>15 events/h were significantly higher than in the COPD group with AHI ≤15 events/h, while the duration of COPD and the proportion of severe COPD were lower than the COPD group with AHI≤ 15 (P<0.05). The scores of Charlson Comorbidity Index, Epworth Sleepiness Scale (ESS) and Sleep Apnea Clinical Score (SACS) in the COPD-OSA group were significantly higher than in the COPD group with AHI≤ 15, with all P values<0.05. Risk factors for AHI>15 OSA coinciding in patients with COPD included BMI, neck circumference, ESS, SACS and CAT (P<0.05). Furthermore, BMI, ESS and CAT were independent risk factors for OSA in COPD patients (P<0.05). Compared with mild or moderate COPD cases, patients with severe COPD (FEV(1)%<50%) had a lower risk of having OSA (β=-0.459, OR=0.632, 95% CI 0.401-0.997, P=0.048). Conclusions: Compared to COPD patients with AHI ≤ 15 events/h, OSA-COPD overlap patients (AHI>15 events/h) had a worse quality of life, more daytime sleepiness and higher prevalence of hypertension. BMI, ESS and CAT were independent risk factors for AHI>15 OSA in patients with COPD. The risk of having OSA in severe COPD patients was lower than cases with mild or moderate COPD.