1048 Prevalence Of Positional Obstructive Sleep Apnea (OSA) In Patients With OSA-COPD Overlap Syndrome

Abstract

Abstract Introduction Positional OSA (non-supine apnea-hypopnea index [AHI] < 5 events/hr) is present in 30% of patients with OSA. We demonstrated that in patients with OSA- COPD overlap syndrome the AHI inversely correlated with the degree of gas trapping, suggesting a stabilizing effect on the upper airway. We hypothesized that sleep position would be less important, resulting in a lower prevalence of positional OSA. Methods Patients underwent a polysomnogram that demonstrated OSA (AHI > 5 events/hr). To confirm COPD, patients had spirometry performed and a chest computed tomography for measurements of percent gas trapping. Results Sixteen patients [6 (38%) males, 55±7 years/old, FEV1 1.2±0.5 L, FEV1 % Predicted 45±19%, FVC 2.3±0.8 L, FVC % Predicted 69±20%, FEV1/FVC 51±12%, BMI 33±9 kg/m2)] were diagnosed with OSA (AHI 15±12 events/hour). Four patients (25%) had positional OSA (AHI 13±6 events/hr, non-supine AHI 1±1 event/hr) compared to 12 patients who were non-positional [AHI 16±13 events/hr (p=0.95)]. There was no difference in age [52±8 and 56±7 yrs (p=0.3)] or severity of obstruction in those with and without positional OSA [FEV1 1.4±4 L and 1.1±0.5 L, (p=0.3), FEV1 % predicted 50±17% and 44±20%, (p=0.7), FVC 2.9±0.8 L and 2.1±0.8 L (p=0.1), FVC % predicted 78±21% and 66±20%, (p=0.3), and FEV1/FVC 50±11% and 51±12%, (p=0.8), respectively]. However, patients with positional OSA were less heavy than those with non-positional OSA [BMI 23±3 and 37±8 kg/m2, respectively (p=0.005)]. Finally, there was no difference in the CT-Derived % Gas Trapping in those with and without positional OSA [48±37% and 36±25%, (p=0.6), respectively]. Conclusion The prevalence of positional OSA in patients with OSA-COPD overlap is similar to OSA patients without COPD. Despite the presence of obstructive disease and gas trapping that may affect upper airway stability, other factors including body position and BMI remain important determinants for developing OSA in patients with COPD. Support R01-HL089856, R01-HL089897