New research out of Spain shows that treatment of obstructive sleep apnea (OSA) with continuous positive airway pressure (CPAP) may lower blood pressure among hypertensive adults.

The study included 394 patients with high blood pressure and non-sleepy OSA (a mild version of the disease that does not result in daytime alertness). Participants were randomized to either receive CPAP or to receive no treatment. Blood pressure of both groups was measured at 3, 6, and 12-month follow-ups.

On average, patients who received CPAP treatment experienced a 2mmHg drop in both systolic and diastolic blood pressure at the end of the study, compared with those who did not receive treatment. Patients that used CPAP for more than 5 hours a night saw the greatest effect on blood pressure.

“This study… shows that CPAP has an effect on cardiovascular outcomes regardless of symptoms,” says Ferran E. Barbé MD, head of the study. “In the future, we would like to know the effects of CPAP treatment on other cardiovascular outcomes such as stroke, myocardial infarction or heart failure.”

The research was presented on May 18 at the American Thoracic Society’s [removed]2008 International Conference[/removed] in Toronto.