Abstract P234: Obstructive Sleep Apnea is More Common in Patients With Masked Uncontrolled Hypertension

Introduction: Masked uncontrolled hypertension (MUCH) is defined as controlled automated office blood pressure (AOBP) in clinic, but uncontrolled out-of-clinic BP by 24-hr ambulatory blood pressure monitoring (ABPM). Prior studies indicate that the prevalence of masked hypertension in patients with newly diagnosed obstructive sleep apnea (OSA) is nearly 30%. In addition, patients with OSA have a higher prevalence of masked hypertension than patients without OSA. Aim: Prospective determination of the prevalence and severity of OSA in patients with MUCH. Methods: In this prospective evaluation, 167 treated hypertensive patients were recruited from the University of Alabama at Birmingham Hypertension Clinic after having controlled BP at three or more clinic visits. All patients were evaluated by AOBP with the BpTRU device, ABPM, and diagnostic polysomnography (PSG) to determine the presence and severity of OSA based on the apnea-hypopnea index (AHI). Out of 153 who completed ABPM, 58 patients were controlled by AOBP and by ABPM, indicating true controlled hypertension and the remaining 95 patients were controlled by AOBP, but uncontrolled by ABPM, indicative of MUCH. 49 true controlled hypertensive and 69 MUCH patients completed PSG. Results: MUCH patients had a mean AHI of 10.3±13.3 compared to 4.5±10.2 events/hr in true controlled hypertension (p =0.045). Overall, the prevalence of OSA was 48.5% in patients with MUCH compared to 26.5% in true controlled hypertension (p = 0.01). Conclusion: MUCH has significant higher prevalence and severity of OSA compared to true controlled hypertension. These findings suggest that untreated OSA may contribute to the development of MUCH.