Evening versus morning dosing regimen drug therapy for hypertension.

Background: Variation in blood pressure levels display circadian rhythms. Complete 24-hour blood pressure control is the primary goal of antihypertensive treatment and reducing adverse cardiovascular outcomes is the ultimate aim. This is an update of the review first published in 2011.

Objectives: To evaluate the effectiveness of administration-time-related effects of once-daily evening versus conventional morning dosing antihypertensive drug therapy regimens on all-cause mortality, cardiovascular mortality and morbidity, total adverse events, withdrawals from treatment due to adverse effects, and reduction of systolic and diastolic blood pressure in people with primary hypertension.

Search Methods: We searched the Cochrane Hypertension Specialised Register via Cochrane Register of Studies (17 June 2022), Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 6, 2022); MEDLINE, MEDLINE In-Process and MEDLINE Epub Ahead of Print (1 June 2022); Embase (1 June 2022); ClinicalTrials.gov (2 June 2022); Chinese Biomedical Literature Database (CBLD) (1978 to 2009); Chinese VIP (2009 to 7 August 2022); Chinese WANFANG DATA (2009 to 4 August 2022); China Academic Journal Network Publishing Database (CAJD) (2009 to 6 August 2022); Epistemonikos (3 September 2022) and the reference lists of relevant articles. We applied no language restrictions.

Selection Criteria: We included randomised controlled trials (RCTs) comparing the administration-time-related effects of evening with morning dosing monotherapy regimens in people with primary hypertension. We excluded people with known secondary hypertension, shift workers or people with white coat hypertension.

Data Collection And Analysis: Two to four review authors independently extracted data and assessed trial quality. We resolved disagreements by discussion or with another review author. We performed data synthesis and analyses using Review Manager Web for all-cause mortality, cardiovascular mortality and morbidity, serious adverse events, overall adverse events, withdrawals due to adverse events, change in 24-hour blood pressure and change in morning blood pressure. We assessed the certainty of the evidence using GRADE. We conducted random-effects meta-analysis, fixed-effect meta-analysis, subgroup analysis and sensitivity analysis.

Main Results: We included 27 RCTs in this updated review, of which two RCTs were excluded from the meta-analyses for lack of data and number of groups not reported. The quantitative analysis included 25 RCTs with 3016 participants with primary hypertension. RCTs used angiotensin-converting enzyme inhibitors (six trials), calcium channel blockers (nine trials), angiotensin II receptor blockers (seven trials), diuretics (two trials), α-blockers (one trial), and β-blockers (one trial). Fifteen trials were parallel designed, and 10 trials were cross-over designed. Most participants were white, and only two RCTs were conducted in Asia (China) and one in Africa (South Africa). All trials excluded people with risk factors of myocardial infarction and strokes. Most trials had high risk or unclear risk of bias in at least two of several key criteria, which was most prominent in allocation concealment (selection bias) and selective reporting (reporting bias). Meta-analysis showed significant heterogeneity across trials. No RCTs reported on cardiovascular mortality and cardiovascular morbidity. There may be little to no differences in all-cause mortality (after 26 weeks of active treatment: RR 0.49, 95% CI 0.04 to 5.42; RD 0, 95% CI -0.01 to 0.01; very low-certainty evidence), serious adverse events (after 8 to 26 weeks of active treatment: RR 1.17, 95% CI 0.53 to 2.57; RD 0, 95% CI -0.02 to 0.03; very low-certainty evidence), overall adverse events (after 6 to 26 weeks of active treatment: RR 0.89, 95% CI 0.67 to 1.20; I² = 37%; RD -0.02, 95% CI -0.07 to 0.02; I² = 38%; very low-certainty evidence) and withdrawals due to adverse events (after 6 to 26 weeks active treatment: RR 0.76, 95% CI 0.47 to 1.23; I² = 0%; RD -0.01, 95% CI -0.03 to 0; I² = 0%; very low-certainty evidence), but the evidence was very uncertain.

Authors' Conclusions: Due to the very limited data and the defects of the trials' designs, this systematic review did not find adequate evidence to determine which time dosing drug therapy regimen has more beneficial effects on cardiovascular outcomes or adverse events. We have very little confidence in the evidence showing that evening dosing of antihypertensive drugs is no more or less effective than morning administration to lower 24-hour blood pressure. The conclusions should not be assumed to apply to people receiving multiple antihypertensive drug regimens.