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

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.