1. Continuous positive airway pressure (CPAP) use in individuals with obstructive sleep apnea (OSA) and resistant hypertension was associated with a decrease in mean 24-hour blood pressure and mean 24-hour diastolic blood pressure, but not mean 24-hour systolic blood pressure.
2. There was a positive correlation between the number of hours of CPAP use and amount of decrease in 24-hour mean blood pressure, 24-hour mean diastolic blood pressure, and 24-hour mean systolic blood pressure.
Evidence Rating Level: 2 (Good)
Study Rundown: Obstructive sleep apnea (OSA) has been associated with a number of cardiovascular diseases, including resistant hypertension. The treatment of choice for OSA is continuous positive airway pressure (CPAP) while sleeping. CPAP use has been found to decrease blood pressure in individuals with OSA. This study was designed to assess the impact of CPAP on individuals with OSA and resistant hypertension. The primary outcome was the change in 24-hour ambulatory mean blood pressure. The secondary endpoints were changes in other blood pressure values, including the diurnal and nocturnal systolic and diastolic blood pressures and changes in nocturnal blood pressure patterns. By the end of the 12 week study, individuals in the CPAP group had a significantly greater decrease in 24-hour mean and diastolic blood pressures, but no change in mean systolic blood pressure when compared to the control group. They also found that individuals in the CPAP group were more likely to display a decrease of at least 10% in the average nighttime blood pressure from the average daytime blood pressure than individuals in the control group. Strengths of this study include the multicenter randomized design and the restriction to individuals with resistant hypertension. Weaknesses of the study include the use of self-reported sleep data and the lack of blinding. While this study does suggest that CPAP is effective in improving resistant hypertension in individuals with OSA, more research should be done to investigate long-term effects of CPAP on resistant hypertension in individuals with OSA.
In-Depth [Open-label, randomized multicenter clinical trial]: This study randomized 194 men and women with OSA and resistant hypertension to receive CPAP or not receive CPAP for 12 weeks. At the end of the 12 week period, the CPAP group had a greater decrease in 24-hour mean blood pressure (3.1 mm Hg, 95% CI 0.6-5.6, p=0.02). Also, the CPAP group had a greater decrease in 24-hour mean diastolic blood pressure (3.2 mm Hg, 95% CI 1.0-5.4, p=0.005), but not in 24-hour mean systolic blood pressure (3.1 mm Hg, 95% CI -0.6-6.7, p=0.10). The proportion of individuals in the CPAP group displaying a decrease of at least 10% in average nighttime blood pressure in comparison to average daytime blood pressure was greater than in the control group (35.9% vs. 21.6%, adjusted odds ratio 2.4, 95% CI 1.2-5.1, p=0.02). Finally, a significant positive correlation between amount of time of CPAP use and amount of decrease in 24-hour mean blood pressure (R=0.29, p=0.006), systolic blood pressure (R=0.25, p=0.02), and diastolic blood pressure (R=0.20, p=0.005) was demonstrated.
By Jeffrey Cohen and Brittany Hasty
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