Prevalence of overlap syndrome in chronic obstructive pulmonary disease patients without sleep apnea symptoms

WOS: 000419935100015PubMed ID: 27148977Background: The co-existence of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) is a common phenomenon referred to as overlap syndrome (OS). In this study, we evaluated the prevalence of OS in mild hypoxemic COPD patients without OSA symptoms and compared characteristics of OS and COPD patients. Methods: Forty-five COPD patients (mean FEV1 1671.3 +/- 532.0 mL) with mild hypoxemia presenting no sleep apnea symptoms (96% men, mean age 67.7 +/- 8.5 years) were involved in this study. Clinical characteristics were recorded, biochemical analysis and polygraphy were performed. Results: Twenty-six patients with a RDI of >= 15 events/h were defined as OS (58%). When OS (n = 26) and COPD without OSA (n=19) groups were compared, BMI (29.6 +/- 6.6 vs 25.6 +/- 4.9 kg/m(2); P = 0.03), TNF-alpha level (24.8 +/- 8.1 vs 3.6 +/- 0.8 ng/mL; P = 0.03) and sleep time with SpO(2) 27.2 kg/m(2) had a sensitivity of 73% and specificity of 68%. Conclusions: This findings support that high prevalence (58%) of OS in COPD patients without OSA symptoms is related to BMI. Therefore, sleep study should be considered in especially overweight or obese COPD patients, even in those without sleep apnea symptoms