African American Study of Kidney Disease and Hypertension ABPM Pilot Study

4\. Methods 4a. Overview The study will be conducted in participants in the African-American Study of Kidney Disease (AASK) Cohort study as a randomized three period cross-over trial. Eighty five percent of AASK cohort participants are currently on an ACE inhibitor or angiotensin receptor blocker; the most commonly used ACE inhibitor is ramipril. The new strategies proposed in this pilot study will remain ramipril-based, to maintain the overall blood pressure control achieved thus far. The antihypertensive regimens proposed are as follows:

• AM dosing of ramipril and other once daily medications in the participants antihypertensive regimen (termed USUAL),
• Bedtime dosing of ramipril and other once a day medications in the participant's antihypertensive regimen (termed HS-DOSING), and
• their current antihypertensive regimen plus an additional antihypertensive agent dosed at bed time; the choice of the additional agent will be tailored based on prespecified clinical guidelines (termed ADD-ON DOSING) The "usual arm" serves as the comparator arm. The "hs dosing" and "add-on dosing" arms test practical strategies that could be tested in a subsequent clinical outcomes trial and that could be implemented in clinical practice. We hypothesize that both arms will reduce nocturnal BP in comparison to "usual dosing". We further hypothesize that the "hs dosing" arm will raise daytime BP somewhat but have no net effect on 24 hour BP and that the "add on dosing" arm will have no effect on daytime BP but lower 24 hour BP. This pilot study will begin after the last scheduled AASK Cohort study visit. Eligible participants will be treated for 6 weeks on each of 3 antihypertensive regimens. The sequence of the regimens will be random. Each period of the three periods will have 2 visits, one visit at 3 weeks and one visit at 6 weeks. In the last week of each 6-week period, a 24-hour ABPM will be obtained. The primary outcome variable is nocturnal BP; each pair wise difference between the regimens will be calculated.