Prevalence, Characteristics, and Association of Obstructive Sleep Apnea with Blood Pressure Control in Patients with Resistant Hypertension

Rationale: Obstructive sleep apnea (OSA) is associated with poor blood pressure (BP) control and resistant hypertension (RH). Nevertheless, studies assessing its prevalence, characteristics, and association with BP control in patients with RH are limited. Objectives: The aim of this multicenter study was to assess the prevalence of OSA in a large cohort of subjects with RH and to evaluate the association of OSA with BP control. Methods: We recruited consecutive subjects with RH from three countries. A formal sleep test and blood pressure measurements, including 24-hour ambulatory blood pressure monitoring, were performed in all participants. Results: In total, 284 subjects with RH were included in the final analysis. Of these, 83.5% (95% confidence interval [CI], 78.7-87.3%) had OSA (apnea-hypopnea index >= 5 events/h); 31.7% (95% CI 26.5-37.3%) had mild OSA, 25.7% (95% CI, 21-31.1%) had moderate OSA, and 26.1% (95% CI, 21.3-31.5%) had severe OSA. Patients with severe OSA had higher BP values than subjects with mild to moderate or no OSA. A greater effect was observed on the average nighttime BP, with an adjusted effect of 5.72 mm Hg (95% CI, 1.08-10.35 mm Hg) in severe OSA compared with participants without OSA. A dose-response association between the severity of OSA and BP values was observed. The prevalence of severe OSA was slightly higher in uncontrolled participants (adjusted odds ratio, 1.69; 95% CI, 0.97-2.99) but was not statistically significant. Conclusions: The present study confirms the high prevalence of OSA in participants with RH. Furthermore, it shows a dose-response association between OSA severity and BP measurements, especially in the nighttime.