Does CPAP treatment in mild obstructive sleep apnea affect blood pressure?

ObjectivesObstructive sleep apnea (OSA) is associated with significant cardiovascular (CV) morbidity. Continuous positive airway pressure (CPAP) is the standard treatment for moderate to severe OSA, resulting in a reduction in CV morbidity. No studies have compared CV outcomes between CPAP and no CPAP in mild OSA (5 ⩾ AHI < 15).MethodsRetrospective cohort study of subjects (age ⩾ 18) with mild OSA diagnosed between 2004 and 2006. Subjects with a history of hypertension, angina, stroke and smoking were excluded. Subjects were stratified into two groups: CPAP (n = 93) or no CPAP (n = 162). The mean blood pressures (MBP) were compared 2 years after the diagnosis of OSA was established.ResultsUnmatched for covariates (age, sex, BMI, neck circumference, AHI, arousal index and family h/o CV disorders), subjects with mild OSA on CPAP had a 1.97 point reduction, and no CPAP resulted in a 9.61 point elevation (p < 0.0001) in MBP. With propensity score matching for covariates, the mean difference in MBP was −1.97 (95% CI: −14.03, −9.92; p < 0.0001) with a sensitivity analysis of 2.646.ConclusionThis study shows an elevation of the MBP in mild OSA patients who were not treated with CPAP. CPAP treatment in mild OSA patients decreased the MBP over a 2-year period.