We assess the prevalence of an apnea hypopnea index (AHI) \> 5 in patients with refractory hypertension referred from a hypertension clinic. Patients with an AHI \>15 are randomized to either continuing their usual pharmacological treatment alone or adding CPAP to their usual treatment, during a 3 month period.
The main endpoint is the comparison of the mean 24h systolic and diastolic blood pressure, as assessed by ambulatory blood pressure monitoring, between both treatment arms. The secondary endpoint is to assess changes in serum markers of endothelial dysfunction and angiogenesis
