0446 Increased Sympathetic Activity Is Associated With Hypertension In Sleep Apnea: BMI Effect. (27th April 2018) - Li, Y
Abstract: Introduction: Hypertension is highly prevalent in obstructive sleep apnea (OSA). OSA patients are known to have increased sympathetic activity that induced by intermittent hypoxia and sleep fragmentation during sleep. It has been suggested that excessive sympathetic activity is one of the underlying mechanisms that associated with hypertension in OSA. However, previous findings of the association between sympathetic activity and hypertension in OSA were inconsistent. The aim of this study was to examine the association between sympathetic activity and hypertension in OSA. Methods: We studied 114 OSA male patients (43.81 ± 9.46y) who underwent one night polysomnography. Twenty-four-hour urinary catecholamnies, including dopamine, epinephrine and noradrenaline levels, were used to measure sympathetic activity. Hypertension was defined based either on blood pressure measures or on diagnosis treatment. Results: Pearson's correlation analyses showed that 24-hour noradrenaline levels were significantly correlated with systolic and diastolic blood pressure (SBP, r=0.18, p=0.05; DBP, r=0.24, p=001) and mean arterial pressure (MAP, r=0.22, p=0.02). Interestingly, this association was modified by overweight (BMI ≥ 25 kg/m2, all p-interaction<0.05). After adjusting for multiple potential confounders, increased noradrenaline levels were significantly associated with increased odds of hypertension in lean OSA patients (OR=1.08, 95%CI=1.01–1.16, P=0.03), whereas this association was lost in overweight or obese patients (OR=0.99, 95%CI=0.98–1.01, P=0.57). Similarly, increased noradrenaline levels were significantly associated with increased SBP (β=0.48, p=0.01), DBP (β=0.39, p=0.03) and MAP (β=0.44, p=0.01) in lean patients but not in overweight or obese patients (all p-values>0.1) while adjusting for multiple potential confounders. No association has been observed between dopamine, epinephrine levels and hypertension. Conclusion: Increased sympathetic activity is associated with increased odds of hypertension in lean but not in overweight or obese OSA male patients. This finding suggests that underlying mechanisms of hypertension may different between lean and overweight patients: lean patients may more relate to excessive sympathetic activity whereas overweight and obese patients may more relate to inflammation. Support (If Any): NNSFC No. 81600068.