Prevalence of Obstructive Sleep Apnea Syndrome in Patients with Resistant Hypertension

Background: Obstructive sleep apnea (OSA) is a significant cardiovascular risk factor, frequently co-existing with systemic hypertension. While the association between OSA and blood pressure elevation is well documented, its specific prevalence and impact among patients with resistant hypertension remain a critical area of clinical investigation. Objective: The primary aim of this study was to evaluate the prevalence and severity of obstructive sleep apnea (OSA) specifically within a cohort of patients with resistant hypertension (RHT). Additionally, we sought to identify the clinical and anthropometric factors that distinguish RHT patients with OSA from non-resistant hypertensive and normotensive controls, thereby clarifying the increased hypoxic burden and polysomnographic differences unique to this high-risk population. Methods: A total of 300 patients presenting with OSA symptoms were included. Participants were classified into three groups: Group 0 (n = 100), normotensive individuals; Group 1 (n = 100), non-resistant hypertension; and Group 2 (n = 100), confirmed resistant hypertension. Standard overnight polysomnography (PSG) was performed on all participants. Demographic data, comorbidities, anthropometric measurements, and PSG parameters were recorded and compared across groups. Results: Of the subjects, 50.3% were female (sex), and the mean age was 49.5 ± 12.3 years. Patients with RHT (Group 2) were significantly older and had a higher prevalence of diabetes mellitus. OSA prevalence was 94% in Group 2 (37% severe), 89% in Group 1 (22% severe), and 74% in Group 0 (only 2% severe). In PSG analysis, AHI and ODI values were significantly higher in hypertensive groups (Groups 1 and 2) compared to normotensive individuals (Group 0), while minimum and mean oxygen saturations were significantly lower. Conclusions: OSA is both more prevalent and more severe in patients with resistant hypertension. Furthermore, hypertensive OSA patients are characterized by an increased hypoxic load compared to normotensives. Systematic investigation and detailed polysomnographic evaluation of OSA are of paramount importance in hypertensive individuals, particularly those with resistant hypertension.