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.


Eligibility Criteria:
Inclusion Criteria:

* Participant in the AASK Cohort Study
* Ability and willingness to provide informed consent
* Completion of a technically adequate ABPM at CO48 AASK cohort study visit.
* Participants must have had at least 2 visits in the last 12 months of the Cohort Study (July 1 2006 to June 1 2007)
* The average of last two BPs measured at least one week apart in the Cohort Study must be less than or equal to 140/90 mm Hg. This would exclude a small percentage of the AASK cohort population; however, it would enroll a group of participants with stable BP who should not require adjustments to their antihypertensive medications during the course of this study.
* Antihypertensive medications at baseline visit: This refers to the participant's antihypertensive regimen at the time of the baseline visit ; the transition period may be used to adjust the participant's antihypertensive regimen to meet these criteria, based on the clinical judgement of the site investigator.

Exclusion Criteria:

* Arm circumference greater than 50 cms.
* ESRD requiring renal replacement therapy or kidney transplantation
* Institutionalized participants
* Shift workers working at night
* MI or CVA within 3 months of AASK Cohort close out visit
* Participants with known ejection fraction less than 40%
* Females known to be pregnant or lactating
* Participants likely to reach end stage renal disease within the next six weeks, in the judgement of the site investigator