Researchers have found that among patients with obstructive sleep apnea and hypertension that requires 3 or more medications to control, continuous positive airway pressure (CPAP) treatment for 12 weeks resulted in a decrease in 24-hour average and diastolic blood pressure and an improvement in the nocturnal blood pressure pattern, compared to patients who did not receive CPAP.

Recent studies have shown that obstructive sleep apnea (OSA) may contribute to poor control of blood pressure and that a very high percentage (more than 70 percent) of resistant hypertension patients have OSA.

Continuous positive airway pressure is the treatment of choice for severe or symptomatic OSA.

According to the researchers, a meta-analysis suggested that CPAP treatment reduces blood pressure levels to a clinically meaningful degree, but whether this positive effect is more pronounced in patients with resistant hypertension is unclear because studies on this issue are scarce and based on single-center approaches.

Miguel-Angel Martinez-Garcia , M.D., Ph.D., of the Hospital Universitario y Politecnico La Fe, Valencia, Spain, and colleagues assessed the effect of CPAP treatment on blood pressure levels and nocturnal blood pressure patterns of 194 patients with resistant hypertension and OSA.

When the changes in blood pressure during the study period were compared between study groups by intention-to-treat, the CPAP group achieved a 3.1 mm Hg greater decrease in 24-hour average blood pressure and 3.2 mm Hg greater decrease in 24-hour diastolic blood pressure, but the difference in change in 24-hour systolic blood pressure was not statistically significant compared to the control group.

In addition, the percentage of patients displaying a nocturnal blood pressure dipper pattern (a decrease of at least 10 percent in the average night-time blood pressure compared with the average daytime blood pressure) at the 12-week follow-up was greater in the CPAP group than in the control group (35.9 percent vs. 21.6 percent). There was a positive correlation between hours of CPAP use and the decrease in 24-hour average blood pressure.

The study was published in journal JAMA.