The HIPARCO-2 study: long-term effect of continuous positive airway pressure on blood pressure in patients with resistant hypertension: a multicenter prospective study

Introduction: Short-term treatment with continuous positive airway pressure (CPAP) produces a clinically significant reduction in blood pressure (BP) in patients with obstructive sleep apnea (OSA) and resistant hypertension. However, it is unknown whether this effect continues over the long-term. Our objective was to assess the effect of long-term CPAP on BP in patients with OSA and resistant hypertension. Methods: The study included 161 patients diagnosed with both OSA [apnea--hypopnea index (AHI) ≥15] and resistant hypertension diagnosed via 24-hour ambulatory BP measurement (24-h ABPM), in whom a second analysis via 24-h ABPM was performed at the end of the follow-up. Results: Patients were followed up within 59 months [interquartile range (IQR): 44–70]. CPAP treatment was prescribed to 82% of the patients (70% with good adherence to CPAP defined as use of CPAP at least 4 h/night). A comparison between the adherent group and nonadherent group (including those with CPAP not prescribed) showed that CPAP adherents had a significant drop in the 24-h BP, both systolic [−3.9 mmHg; 95% confidence interval (CI): −8.1 to 0.3] and diastolic pressure (−3.5 mmHg [95% [CI]: −6.4–0.5]), with a higher magnitude during the night (−5.5 and −4.9 mmHg, respectively). The CPAP adherent group needed a mean of 1.1 less antihypertensive drugs (particularly spironolactone). Finally, there was a positive correlation between the drop in 24-h SBP and the hours of CPAP use ( r = 0.24; P = 0.01). Conclusion: Good adherence to long-term CPAP treatment largely succeeded in significantly reducing BP in those patients with OSA and resistant hypertension, despite the use of a lower number of antihypertensive drugs.