CPAP effects on blood pressure in different OSA phenotypes – a meta-analysis

<bold>Introduction:</bold> The causal relationship between obstructive sleep apnea (OSA) and arterial hypertension is well established. In an unselected patient population with OSA, continuous positive airway pressure (CPAP) lowers blood pressure (BP) marginally. <bold>Aims and Objectives:</bold> To study the different effects of CPAP on office, 24h, diurnal, and nocturnal BP in different OSA phenotypes, including different OSA severities, initial blood pressure, comorbidities, and usage patterns. <bold>Methods:</bold> We conducted a study-level meta-analysis, including 75 RCTs that compared CPAP treatment to passive controls and performed subgroup analysis and meta-regressions. <bold>Results:</bold> CPAP treatment reduced office, 24h, diurnal, and nocturnal systolic BP (SBP) by -2.48 (95%CI -3.78, -1.18; n=40), -2.57 (95%CI -3.56, -1.58; n=29), -2.23 (95%CI -3.20, -1.27; n=32), and -3.46 (95%CI -4.44, -2.48; n=32) mmHg, respectively. In a meta-regression, higher CPAP usage hours as higher baseline 24h and diurnal SBP were significantly associated with greater BP reduction (all p<0.05). In subgroup analysis, reduction in 24h, diurnal, and nocturnal SBP was greater in studies with baseline apnea-hypopnea index ≥30/h (−3.18 vs -1.49, -2.38 vs -1.35, -3.64 vs -3.10 mmHg, respectively) and a sleepy patient population (baseline Epworth Sleepiness Scale ≥10) (−2.67 vs -1.87, -3.88 vs -1.59, -4.96 vs -4.02 mmHg, respectively). CPAP usage ≥5h/night had a higher impact on BP lowering for office, 24h, and nocturnal SBP (−4.01 vs -1.44, -4.18 vs -2.10, -4.23 vs -1.58 mmHg, respectively). <bold>Conclusions:</bold> We displayed that CPAP effects on BP in OSA patients are not only dependent on different aspects of BP but on underlying OSA severity and comorbidities.