Morning Versus Evening Dosing of Antihypertensive Medications: A Pilot Study to Assess Feasibility and Efficacy

Background Hypertension is a major risk factor for cardiovascular and renal disease, and a leading cause of premature mortality worldwide. Early hypertension studies showed that treating elevated blood pressure (BP) reduces patients' risk of cardiovascular disease and all-cause mortality. In subsequent research, patients achieved greater improvement in cardiovascular outcomes when their treatment was aimed at a moderate systolic BP target (<150mmHg) than at higher targets. Although observational data suggest that even lower BP targets may be beneficial, this has not been seen in randomized trials; instead, "intense" treatment of hypertension (i.e., to a target systolic BP <120mmHg) was found to have no effect on participants' risk for renal disease, cardiovascular disease, or all-cause mortality. Similarly negative findings were reported in studies that enrolled participants with chronic kidney disease (CKD) and diabetes; all failed to demonstrate a benefit to intensive lowering of clinic BP.

One potential explanation for this apparent lack of benefit of intense BP targets is that the study protocols targeted reductions in clinic BP rather than ambulatory BP. Ambulatory BP monitoring (ABPM) allows for assessment of BP throughout the day and night. Of all the BP measurements, nighttime systolic BP appears to be the best predictor of cardiovascular disease and all-cause mortality. In fact, in most observational studies, clinic BP is no longer a predictor of adverse events after adjusting for nighttime BP. Importantly, elevated nighttime BP is a modifiable risk factor; evening dosing of antihypertensive medications lower nighttime BP and reduces proteinuria. In a large, randomized controlled trial, evening dosing of antihypertensive medications reduced the hazard rate for major cardiovascular events by 67%. Findings were similar in the subgroup of participants with CKD. However, this single-center study was designed to evaluate cardiovascular outcomes, not progression of CKD. The long-term effect of nighttime dosing of antihypertensive medications on progression of CKD is unknown.

To address this important gap in knowledge, the investigators plan to conduct a pragmatic, randomized controlled trial. 3600 participants at risk for progression of CKD who are taking ≥1 antihypertensive medication once daily will be randomized to morning versus evening dosing of at least one antihypertensive medication. The purpose of the proposed study is to obtain pilot data demonstrating the feasibility of the trial and the efficacy of the intervention.

Overview of Trial Design The study will be conducted in the renal clinic at University of Minnesota Medical Center (UMMC). Eligible patients will have chronic kidney disease and be taking a once daily antihypertensive medication. Participants will be randomized to receive their once daily antihypertensive medication in the morning or the evening. Medication therapy management with a focus on antihypertensive medications will take place at the time of a clinic visit or via phone after the clinic visit. Adherence to medications will be assessed 3-6 weeks after the clinic visit.

Objective The primary objective of this pilot study is to demonstrate 1) the feasibility of a simple randomized trial and 2) the efficacy of medication therapy management for assigning participants to take a once daily antihypertensive medication either in the morning or in the evening.