THE RESPIRATORY AROUSAL INDEX IS MORE SIGNIFICANTLY ASSOCIATED WITH THE PRESENCE OF HYPERTENSION THAN THE APNEA-HYPOPNEA INDEX (AHI) IN PATIENTS WITH OBSTRUCTIVE SLEEP APNEA

Objective: The prevalence of hypertension (HTN) is higher in obstructive sleep apnea (OSA) patients. Increased sympathetic drive might be the leading mechanism of HTN in OSA. We aimed to identify the association between the sleep-related indices and hypertension, and the predictive value of these indices for prevalent HTN in OSA patients. Design and method: 206 patients (197 males, 44 ±11 years) with newly diagnosed moderate-to-severe OSA [apnea-hypopnea index (AHI) >=15] were enrolled from May 2009 to September 2012. All patients underwent full-night laboratory polysomnography and transthoracic echocardiography. Results: Among 206 patients, 32% (65/206) had HTN. HTN group was older, and had a higher AHI, oxygen desaturation index (ODI), respiratory arousal index (RAI), and lower e’ velocity, higher E/e’ than non-HTN group (all p<0.05). Multivariate logistic regression analysis revealed that RAI and age were significantly associated with HTN after adjustment of AHI, ODI or lowest saturation <85%. The area under the receiver operating curve for RAI was 0.642 (p=0.001).Conclusions: Our results suggest that RAI better reflects the contribution to the activation of sympathetic tone leading to the prevalent HTN rather than AHI, ODI or lowest saturation.