Clinical question: What is the effect of continuous positive airway pressure (CPAP) or supplemental oxygen on ambulatory blood pressures and markers of cardiovascular risk when combined with sleep hygiene education in patients with obstructive sleep apnea (OSA) and coronary artery disease or cardiac risk factors?
Background: OSA is considered a risk factor for the development of hypertension. One meta-analysis showed reduction of mean arterial pressure (MAP) with CPAP therapy, but randomized controlled data on blood pressure reduction with treatment of OSA is lacking.
Study design: Randomized, parallel-group trial.
Setting: Four outpatient cardiology practices.
Synopsis: Patients ages 45-75 with OSA were randomized to receive nocturnal CPAP and healthy lifestyle and sleep education (HLSE), nocturnal oxygen therapy and HSLE, or HSLE alone. The primary outcome was 24-hour MAP. Secondary outcomes included fasting blood glucose, lipid panel, insulin level, erythrocyte sedimentation rate, C-reactive protein (CRP), and N-terminal pro-brain naturetic peptide.
Participants had high rates of diabetes, hypertension, and coronary artery disease. At 12 weeks, the CPAP arm experienced greater reductions in 24-hour MAP compared to both the nocturnal oxygen and HSLE arms (-2.8 mmHg [P=0.02] and -2.4 mmHg [P=0.04], respectively). No significant decrease in MAP was identified in the nocturnal oxygen arm when compared to the HSLE arm. The only significant difference in secondary outcomes was a decrease in CRP in the CPAP arm when compared to the HSLE arm, the clinical significance of which is unclear.
Bottom line: CPAP therapy with sleep hygiene education appears superior to nocturnal oxygen therapy with sleep hygiene education and sleep hygiene education alone in decreasing 24-hour MAP in patients with OSA and coronary artery disease or cardiac risk factors.
Citation: Gottlieb DJ, Punjabi NM, Mehra R, et al. CPAP versus oxygen in obstructive sleep apnea. N Engl J Med. 2014;370(24):2276-2285.