Nocturia is an independent predictive factor of prevalent hypertension in obstructive sleep apnea patients

Objective: The aim of this study was to determine whether nocturia is an independent predictor for prevalent hypertension in obstructive sleep apnea (OSA). Methods: We analyzed data from a national prospective clinical cohort of OSA patients participating in the French national prospective registry. Anthropometric data, comorbidities, OSA severity, and number of voids/night were included in multivariate analyses to determine the independent variables associated with prevalent hypertension. Results: A total of 22,674 OSA patients were included, of which 11,332 were hypertensive. The prevalence of hypertension among OSA patients was about 1.3 times higher in patients suffering from nocturia at 61.45% versus 46.52% in hypertensive and non-hypertensive OSA patients (p < 0.001). There was a significant positive relationship between hypertension and the severity of nocturia beyond two voids/night: two voids/night versus none: odds ratio (OR) = 1.270 (95% confidence interval (CI) = 1.175; 1.372), three voids/night versus none: OR = 1.422 (95% CI = 1.293; 1.565), and four voids/night versus none: OR = 1.575 (95% CI = 1.394; 1.781). The strength of the association was enhanced in patients over 64 years of age. Conclusions: Nocturia is a strong independent predictor of prevalent hypertension in OSA. This association exhibited a "dose-response" relationship beyond two voids/night. The resolution of nocturia after continuous positive airway pressure (CPAP) treatment might be an important outcome to consider for the response of hypertension to CPAP. (C) 2014 Elsevier B.V. All rights reserved.