Effects of Continuous Positive Airway Pressure on Central and Peripheral Blood Pressure in Patients with Uncontrolled Hypertension and Obstructive Sleep Apnea: The Randomized Controlled MORPHEOS Clinical Trial.

Rationale: Previous studies evaluating the effect of continuous positive airway pressure (CPAP) on blood pressure (BP) among patients with obstructive sleep apnea (OSA) showed variable results. Moreover, several studies recruited patients with normal or controlled BP, and compliance with antihypertensive drug treatment was not monitored. In addition, very few studies investigated central BP in this scenario.

Objectives

To evaluate whether OSA treatment is able to reduce central and peripheral BP in patients with uncontrolled hypertension (HTN) despite well-documented use of antihypertensive treatment.

Methods

MORPHEOS is a multicenter randomized controlled trial designed to evaluate the effects of CPAP or placebo (nasal dilator strips [NDSs]) for 6 months in patients with moderate to severe OSA and uncontrolled HTN on office BP, ambulatory BP monitoring (ABPM), and central BP (coprimary endpoints). Uncontrolled HTN was defined by at least one abnormal parameter on ABPM after 1 month and ⩾80% adherence to medication based on a pill count. Pill counts, adherence to CPAP or NDS, and office BP were determined once per week in the first month and monthly thereafter.

Results

A total of 123 patients completed the study (NDS, n = 64; CPAP, n = 59). The two groups were similar at baseline. Adherence to NDS (⩾80%) and CPAP (⩾4 hours per night) were 98.3% and 81.7%, respectively. Compared with NDSs, office systolic BP (Δ = -10 ± 16 mm Hg; P < 0.001) and diastolic BP (Δ = -7 ± 12 mm Hg; P = 0.001) were reduced significantly in the CPAP group. Despite the BP-lowering effect of CPAP not reaching statistical significance for the ABPM parameters, the rate of 24-hour ABPM control (<130/80 mm Hg) was higher in the CPAP group than in the NDS group (40.7% vs. 20%; P = 0.024). Central diastolic BP was reduced significantly (Δ = -6 ± 9 mm Hg; adjusted P = 0.029).

Conclusions

CPAP improves the rates of BP control in patients with OSA and uncontrolled HTN with regular use of medications. Clinical trial registered with www.clinicaltrials.gov (NCT02270658).