Sleep-related breathing disorder is an independent risk factor for systemic hypertension

The exact influence of sleep-related breathing disorder (SRBD) on blood pre ssure control remains unknown. We investigated the influence of different d egrees of SRBD on daytime blood pressure and its association to documented hypertension by examining 1,190 consecutive patients referred for diagnosis of SRBD. The protocol includes clinical interview, physical examination, o ffice blood pressure measurement, cholesterol, and blood gas analysis. Unat tended home monitoring of nocturnal breathing was performed for assessment of SRBD activity (respiratory disturbance index [RDI]). RDI was independent ly and linearly associated with systolic blood pressure (unstandardized coe fficient [B] = 0.07 +/- 0.03, p = 0.03), diastolic blood pressure (B = 0.07 +/- 0.02, p = 0 < 0.001), and heart rate (B = 0.10 +/- 0.02 p < 0.001) at rest. The relative risk for hypertension (blood pressure a 160/95 mm Hg) in creased with SRBD severity (odds ratio [OR], 4.15 for RDI greater than or e qual to 40 versus < 5 [95% CI, 2.7 to 6.5]). This relative risk was also el evated in younger (less than or equal to 50 yr) compared with older patient s (> 50 yr) (OR, 7.15 versus 2.70 for RDI a 40 versus < 5). These cross-sec tional clinical data suggest a relationship between SRBD severity and systo lic blood pressure, diastolic blood pressure, and heart rate after control for confounders such as body mass index (BMI), age, alcohol/nicotine consum ption, cholesterol level, and daytime Po-2 and Pco(2). SRBD is an independe nt risk factor for systemic hypertension with an increased likelihood in su bjects less than or equal to 50 yr of age.