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S3 Effect of continuous positive airway pressure on blood pressure in patients with minimally symptomatic obstructive sleep apnoea: a meta-analysis using individual patient data from four randomised controlled trials
  1. DJ Bratton1,
  2. JR Stradling2,
  3. F Barbe3,
  4. M Kohler4
  1. 1MRC Clinical Trials Unit, London, UK
  2. 2Oxford Centre for Respiratory Medicine and NIHR Biomedical Research Centre, Oxford, UK
  3. 3Department of Pneumology, Biomedical Research Institute, Lleida, Spain
  4. 4Division of Pulmonology, University Hospital Zurich, Zurich, Switzerland


Objective To evaluate the effectiveness of continuous positive airway pressure (CPAP) in reducing blood pressure, sleepiness and sleep apnoea severity in patients with minimally symptomatic obstructive sleep apnoea (OSA).

Design Systematic review and meta-analysis using individual participant data.

Data sources Individual patient data were obtained from eligible randomised controlled trials found by searching the electronic databases Medline, Embase and the Cochrane Central Register of Controlled Trials and reference lists of all identified articles.

Eligibility criteria for selecting studies Trials were eligible if they included patients with minimally symptomatic OSA, had randomised them to receive CPAP or either sham-CPAP or no CPAP, and had measured blood pressure at baseline and at a follow-up visit.

Results Five eligible trials were found (1219 patients) from which the necessary data from four studies (1206 patients) was obtained. There was some evidence that CPAP treatment was associated with a small increase in systolic blood pressure of 1mmHg (95% confidence interval -0.1 to 2.2), p = 0.079, with a larger increase in those patients using CPAP less than four hours/night ( + 2.7mmHg, 95% CI (1.1 to 4.2), p = 0.001). There was no overall effect on diastolic blood pressure (DBP), however, there was evidence of a reduction in DBP in patients using CPAP more than four hours/night (-1.2mmHg, 95% CI (-2.1 to -0.3), p = 0.013) and an increase in those using it less than four hours/night ( + 1.2, 95% CI (0.1 to 2.3), p = 0.035). CPAP treatment reduced both subjective sleepiness and OSA severity (both p<0.001), with larger reductions in patients using treatment more than four hours/night.

Conclusions Although CPAP treatment reduces OSA severity and sleepiness, it seems not to have a beneficial effect on blood pressure (and possibly a detrimental effect on systolic BP) in patients with minimally symptomatic OSA,unless they use CPAP for more than four hours per night.

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