A12854 Severity of obstructive sleep apnoea is not associated with nocturnal blood pressure fluctuation in elderly hypertensive patients receiving amlodipine

Abstract

Objectives: Obstructive sleep apnoea (OSA) is associated with increased variability in nocturnal blood pressure (BP). Calcium channel blockers (CCBs) are superior to other classes of antihypertensives in decreasing BP variability. We investigated whether OSA severity is associated with nocturnal BP variability in elderly hypertensive patients treated with amlodipine. Methods: We measured systolic and diastolic BP and pulse rate (PR) automatically during sleep at an interval of an hour once a week using an electronic sphygmomanometer in twenty-three hypertensive patients (≥65 years) receiving amlodipine. We calculated the coefficient of variation (CV) in data from 4 consecutive measurements. All patients underwent a home-based portable sleep study. Results: There were no differences in the average and CV of BP and the average PR between patients without OSA or with mild OSA and those with moderate to severe OSA as categorized by the respiratory disturbance index (RDI) and 3% oxygen desaturation index (ODI). The CV of PR in patients with moderate to severe OSA was lower than those of patients without OSA or with mild OSA categorized by 3% ODI. BMI was correlated with RDI and 3% ODI (r = 0.58 and 0.50, respectively). RDI and 3% ODI were not correlated with the CV of BP. The CV of PR was positively correlated with both RDI and 3% ODI (r = 0.42 and 0.45, respectively). Conclusion: The severity of OSA was associated with PR variability but not BP variability in older patients receiving CCB. Our results suggest the need for future studies to determine whether CCBs can suppress the influence of OSA on BP fluctuation during sleep.