Treating Obstructive Sleep Apnea

Abstract

Obstructive sleep apnea (OSA), a common disorder, increases the 4-year risk of developing hypertension by ≈3-fold.1 In an uncontrolled trial, treatment of OSA when present in drug-resistant hypertension by nasal continuous positive airway pressure (CPAP) achieved substantial reductions in both nighttime and daytime blood pressure (BP).2 However, in controlled and uncontrolled studies involving small cohorts of patients with OSA with stage 1 hypertension, prehypertension, or normal BP, the short-term use of CPAP had less or no effect on BP. A meta-analysis in the present issue of Hypertension 3 attempts to estimate the effect of this intervention on BP. The authors identified all of the published trials that reported BP as a primary or a secondary end point in which adults with OSA diagnosed by polysomnography were randomly allocated to therapeutic CPAP or not for ≥2 weeks. These 16 trials involved 818 participants (86.3% men; mean age: 51 years; mean apnea-hypopnea index: 36.2 events per hour) treated for ≤24 weeks. From the 15 trials that reported systolic and diastolic BP, the authors calculated a significant mean net reduction of 2.46/1.83 mm Hg with CPAP and, from the 7 trials that reported mean arterial BP, a significant net reduction of 2.22 mm Hg. By comparison, in a previous meta-analysis restricted to 12 trials in which the primary variable of interest was 24-hour mean ambulatory BP, the calculated net decrease was still significant at 1.69 mm Hg.4 In the present analysis by Bazzano et al,3 the mean net change in systolic BP tended to correlate with the average nightly CPAP use (Figure 5 in Reference 3; P =0.13). These authors concluded that CPAP decreases BP among those with OSA, and treating OSA with CPAP may help prevent hypertension. There is increasing awareness of the adverse interactions between OSA …