Objective: To evaluate the impact of a long-term use of CPAP on clinic and ambulatory blood pressure (BP) in patients with resistant hypertension (RHT) and obstructive sleep apnea (OSA)
Design and method: An observational prospective study was performed in 66 patients with RHT and moderate/severe OSA (AHI > 15/hour), using CPAP for at least 12 months. Clinic BP and 24-hour BP were obtained before and after follow-up. Primary outcomes were changes in clinic and ambulatory BPs, and BP control. The differences of BP from the beginning to the end of the study were evaluated with a paired t test, adjusted by baseline BP. A per-protocol analysis was performed limited to patients with uncontrolled ambulatory BP levels at baseline.
Results: 66 patients [64% females, mean (SD) age: 62 (8) years] were followed-up for a median of 20 [15-35] months. They used a median of 5 [3-8] antihypertensive drugs and had mean (SD) clinic BPs of 151 (26)/86 (17) mm Hg and ambulatory 24-hour BPs of 128 (17)/75 (11) mmHg; 61% of them had uncontrolled ambulatory BP levels at baseline. The average use of CPAP treatment was 5 (1.9) hours per night, with 78% using it at least 4 hours per night. A significant reduction of 24-hour (-3.7 [-7.7 to + 0.2] mmHg, p = 0.04) and daytime (-5.6 [-10.1 to - 1.1] mm Hg, p = 0.02) systolic ambulatory BP was found. Controlled ambulatory BP increased from 39% to 57%. In a per-protocol analysis, 48 patients with baseline uncontrolled ABPM were evaluated. They achieved a significant decrease in clinic systolic BP (-7.4 [-11.4 to + 3.2] mmHg, p = 0.04) and in systolic and diastolic ambulatory BP in all periods: 24-hour (14.6 [-21.0 to - 8.2]/-7.4 [-10.8 to -2.8]) mmHg, daytime (-17.3 [-10.8 to - 3.8]/-7.7[-11.3 to -4.3] mmHg) and nighttime (-8.6 [-15.2 to - 1.9) / -4.1 [-7.1 to - 1.0]) mmHg.
Conclusions: The treatment of OSA with long-term use of CPAP significantly reduces blood pressure in patients with resistant hypertension, especially in those with uncontrolled ambulatory BP at baseline.
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