P004 Gender differences in heart rate during respiratory events and arousals in patients with obstructive sleep apnea and chronic obstructive pulmonary disease overlap syndrome

Abstract Introduction Obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) are associated with increased sympathetic nervous activity, and patients affected by both disorders have a higher risk of mortality than patients with COPD or OSA alone. This preliminary study compared HR during respiratory events and respiratory arousals in men and women with OSA-COPD overlap syndrome. Methods 121 individuals with both OSA (AHI>=5) and COPD (86 male, 65.4±7.5 years; 35 female, 62.7±10.0 years) were identified from a retrospective clinical dataset of 989 individuals who were studied with clinical diagnostic polysomnography. Continuous electrocardiography was extracted, and the mean HR was calculated during respiratory events terminated with arousals, respiratory arousals, and non-event baseline. The duration of respiratory arousals was calculated. Results The mean HR during respiratory-arousals was higher in women compared to men (72.4±5.0 vs 69.3±5.3; p<0.05 Wilcoxon rank-sum test). The duration of respiratory arousals was also greater in women (10.1±1.0 vs 9.3±0.7; p<0.05). The difference in HR in respiratory arousal compared with baseline was greater in females (5.2±1.3 vs. 2.3±0.9, p<0.05) The mean HR during respiratory events did not significantly differ between males and females. Discussion Literature has previously speculated that women with OSA-COPD overlap have greater sympathetic modulation of heart rate. This is consistent with our results showing higher HR during respiratory-arousals (and greater HR increase relative to baseline) in women. However, substantial further work is required to distinguish the relative effects of gender, OSA-COPD overlap, and numerous other confounding factors (i.e., OSA severity and endotype/phenotype, age, and sleep state).