Does Obstructive Sleep Apnea Influence Blood Pressure and Arterial Stiffness in Response to Antihypertensive Treatment?

Untreated obstructive sleep apnea (OSA) is common in patients with hypertension and may impair blood pressure (BP) and target-organ damage responses to antihypertensive therapy. In this study, we recruited hypertensive patients who underwent treatment with a 30-day regimen of hydrochlorothiazide 25 mg plus enalapril (20 mg BID) or losartan (50 mg BID) and were assessed with a baseline clinical evaluation, polysomnography, 24-hour ambulatory BP monitoring, and carotid-femoral pulse wave velocity. All the examinations except for polysomnography were repeated at 6 and 18 months of follow-up. We studied 94 hypertensive patients (mean age, 55 +/- 9 years). The frequency of OSA was 55%. Compared with baseline, we did not observe significant differences between groups in 24-hour BP, daytime systolic and diastolic BPs, or night-time systolic BP at 6 and 18 months. The BP control rate at 24 hours (<130/80 mmHg) was similar between the groups (baseline, 42.3% versus 45.2%; 6 months, 46.9% versus 57.5%; 18 months, 66.7% versus 61.5%). However, patients with OSA had higher night-time diastolic BP decrease than did the non-OSA group (6 months, -4.9 +/- 11.8 versus -0.3 +/- 10.3 mmHg; 18 months, -6.7 +/- 11.1 versus -1.2 +/- 10.6 mmHg; P=0.027). There were no differences in the number and class of antihypertensive medications prescribed during follow-up. In terms of arterial stiffness, patients with OSA had higher pulse wave velocity than did patients without OSA at baseline (10.3 +/- 1.9 versus 9.2 +/- 1.7 m/s; P=0.024), but both groups had similar decreases in pulse wave velocity during follow-up. In conclusion, with combined antihypertensive treatment aimed at controlling BP, hypertensive patients with OSA had similar 24-hour BP and arterial stiffness to those without OSA.