Association between refractory hypertension and obstructive sleep apnea

Background Obstructive sleep apnea (OSA) increases the risk for mild hypertension, but its relationship to refractory hypertension (RHT) has not been systematically examined. We previously reported a high prevalence of OSA in patients with RHT, but did not have a control group with which to compare. Rapid eye movement (REM) sleep deprivation can raise blood pressure in animals. However, a potential relationship of OSA and REM sleep time with RHT has not been examined. Objective To determine whether, compared with patients with well controlled hypertension, those with RHT have a higher prevalence of OSA (apnea-hypopnea index >= 10 per hour of sleep) and shorter REM sleep time. Methods We compared the prevalence of OSA and sleep structure in 42 patients with RHT with 22 patients with controlled hypertension, matched for age, sex and BMI. Results Compared with the controlled hypertension group, the RHT group had a significantly higher prevalence of OSA (81 versus 55%, P = 0.03) and less REM sleep time (47.0 +/- 4.5 versus 63.2 +/- 4.9 min, P = 0.02). Multivariate analysis revealed significantly increased odds of having RHT associated with OSA independent of other risk factors (adjusted odds ratio, 3.994; 95% confidence interval, 1.191-13.388). Reduced REM sleep time was also independently associated with the presence of RHT (adjusted odds ratio, 1.025; 95% confidence interval, 1.002-1.049). Conclusion OSA and reduced REM sleep time are associated with increased odds of having RHT and, therefore, may play roles in its pathogenesis. J Hypertens 27: 1439-1445 (C) 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins.