Evaluating the Optimal Timing for Medications in Patients with Essential Hypertension – A Meta-Analysis of Randomized Controlled Trials

Background: Studies has indicated that administering medication at different times may result in varying effects on reducing high blood pressure and outcomes. Regrettably, those numerous studies exhibit contradictory findings. Objective: This meta-analysis aimed to assess the efficacy of administering drugs for hypertension in the morning compared to the evening. Method: A search was conducted using various online databases, including PubMed, Scopus, ScienceDirect, and ProQuest, to locate randomized controlled trials (RCTs) that were written in English and published before October 2023. The RCTs examined how reduction of blood pressure, cardiovascular events, heart failure, and cardiovascular death, were affected by dosing in the morning and evening. Independently, two reviewers extracted data and evaluated the quality of the trials. Meta-analysis was performed using Review Manager 5.4 software. Result: Initial screening yielded 551 studies, 12 RCTs involving 5157 patients with hypertension met the inclusion criteria in this study. Compared to morning treatment, evening administration of hypertensive medication could decrease 24-h systolic blood pressure (SBP) (MD = 3.79, 95%CI = 0.65 – 6.93, p = .02), 48-h SBP (MD = 1.46, 95%CI = 0.53 – 2.39, p = .002), cardiovascular events (OR = 3.3, 95%CI = 2.15 – 3.85, p<.001), heart failure (OR = 2.88, 95%CI = 2.03 – 5.35, p<.001), and cardiovascular death (OR = 4.45, 95%CI = 1.83 – 10.81, p = .001). Conclusion: This meta-analysis showed that administering medication in the evening could reduce systolic blood pressure, cardiovascular events, heart failure, and cardiovascular death more effectively than in the morning.