Clinical Features of Obstructive Sleep Apnea That Determine Its High Prevalence in Resistant Hypertension

Purpose: Resistant hypertension (HTN) occurs in 15-20% of treated hypertensive patients, and 70-80% of resistant hypertensive patients have obstructive sleep apnea (USA). The characteristics of resistant HTN that predispose patients to USA have not been reported. Therefore, we aimed to determine the clinical, laboratory, and polysomnographic features of resistant HTN that are significantly associated with USA. Materials and Methods: Hypertensive patients (n=475) who underwent portable polysotimography were enrolled. The patients were categorized into controlled (n=410) and resistant HTN (n=65) groups. The risk factors for the occurrence of USA in controlled and resistant hypertensive patients were compared, and independent risk factors that are associated with USA were analyzed. Results: Out of 475 patents, 359 (75.6%) were diagnosed with USA. The prevalence of USA in resistant HTN was 87.7%, which was significantly higher than that in controlled HTN (73.7%). Age, body mass index, neck circumference, waist circumference, and hip circumference were significantly higher in USA. However, stepwise multivariate analyses revealed that resistant HTN was not an independent risk factor of OSA. Conclusion: The higher prevalence and severity of USA in resistant HTN may be due to the association of risk factors that are common to both conditions.