Effects of chlorthalidone plus amiloride compared with amlodipine on short-term blood pressure variability in individuals with hypertension and obstructive sleep apnea: a randomized controlled trial

Abstract

Objective To compare the effects of chlortalidone plus amiloride and amlodipine on blood pressure (BP) variability in patients with hypertension and obstructive sleep apnea syndrome (OSA). Methods A randomized, controlled, double-blind trial enrolled men and women aged 40 years or older with a diagnosis of OSA (apnea-hypopnea index 10–40 apneas/h of sleep) confirmed by overnight laboratory polysomnography and systolic BP 140–159 mmHg or diastolic BP 90–99 mmHg. Participants were randomized to receive chlortalidone 25 mg plus amiloride 5 mg daily or amlodipine 10 mg daily for 8 weeks. BP variability was calculated from 24-hour ambulatory BP monitoring at baseline and follow-up using the following indices: SD, coefficient of variation, average real variability (ARV), time-rate index, and variability independent of the mean (VIM). Results The study included 65 patients, with 33 assigned to the chlortalidone plus amiloride group and 32 to the amlodipine group. Participants in both groups had similar baseline characteristics. Short-term BP variability decreased within groups for SD and ARV indexes for 24-hour systolic BP and daytime systolic BP, but statistically significant time*group interactions were found for sleep systolic SD and VIM, with greater reduction in patients treated with amlodipine. Conclusion In brief, our study has shown that the use of chlorthalidone in combination with amiloride and amlodipine produces comparable effects on short-term BP variability in patients with hypertension and OSA. Therefore, our findings suggest that BP variability may not be a significant factor when choosing between these medications for the treatment of hypertension and OSA.