Predictors of BP reduction in patients with OSA treated with CPAP therapy – an individual patient data meta-analysis

Continuous positive airway pressure (CPAP) leads to a variable blood pressure (BP) reduction in patients with obstructive sleep apnoea (OSA). The aim was to identify predictors of CPAP-related BP changes by analysing individual data from randomised controlled trials (RCTs) investigating the effect of CPAP versus no CPAP on BP. Outcomes were treatment effect on office and 24h-BP, both in the entire study population and in groups stratified by baseline BP (uncontrolled/controlled HT, normotension), and predictors of BP treatment response using regression models. Individual patient data from 34 parallel-group RCTs (n=7,456, 72% males, body mass index, BMI 31.9 ± 14.8 kg/m2, age 58.6 ± 10.9 years, apnoea-hypopnoea index, AHI 35.5 ± 20.6 /hour, SpO2 min 78.14 ± 7.92) were analysed. A consistent BP lowering effect was seen in patients with uncontrolled HT at baseline (mean [95%CI]; office: SBP -2.33 [-4.01; -0.65], DBP -1.53 [-2.59; -0.46], 24h: SBP -3.59 [-6.19; -1.00], DBP -3.21 [-4.85; -1.57]) with no significant BP change in those with controlled HT or in normotensives. Multivariate analysis showed that higher BP at baseline was an independent predictor of BP reduction versus controls for both office and 24h-BP, while younger age and more severe nocturnal oxygen desaturations predicted significant BP drop for office BP. (Figure 1) The BP lowering effect of CPAP is driven mainly by OSA patients with uncontrolled BP at baseline. Younger age and more severe nocturnal oxygen desaturations predicted the BP drop on CPAP.