The Effects of Potassium on Glucose Metabolism in African Americans
Status:
Completed
Trial end date:
2016-02-29
Target enrollment:
Participant gender:
Summary
African Americans suffer a disproportionately high risk of diabetes compared to other
Americans. Reasons for race disparities in diabetes incidence are not completely understood.
Although a difference in prevalence of obesity does explain a significant portion of the
racial disparity in diabetes risk, it does not explain all of this disparity. Strategies to
control the diabetes epidemic and reduce its racial disparity often overlook preventive
measures. Currently, the most powerful known strategy for preventing diabetes is weight loss
in the overweight/obese. However, because weight loss is often difficult to achieve and
maintain, other opportunities to prevent diabetes should be identified, particularly in
African Americans. Among potential novel opportunities is correction of low or low-normal
potassium levels (hypokalemia). In secondary analyses, we have found low-normal potassium (K)
to be a novel risk factor for diabetes; and we have found that this association between low-K
and diabetes risk may be stronger in African Americans compared to whites. Therefore, a
previously unrecognized alternative or adjunct strategy for preventing diabetes, particularly
in African Americans, may involve correction of low or low-normal K levels (hypokalemia).
Large-scale, adequately-powered, randomized controlled trials are needed to establish the
effectiveness of this approach. However, prior to those trials, the pathophysiology of the
association between low K and poor glucose metabolism must be understood. This pilot clinical
trial will begin to determine the effect of K supplementation on measures of glucose
metabolism in African Americans.
In this pilot clinical trial, 30 African Americans with prediabetes and a low-normal serum K
[<4.0 milliequivalent/Liter (Eq/L)] will be randomized to K-supplements, 20mEq (2-10mEq
tablets) twice daily or a matching placebo capsules twice daily. Prior to randomization,
baseline measures will be taken including measures of glucose metabolism with a 3-hour oral
glucose tolerance test (OGTT), baseline chemistries and a baseline 24-hour urinary potassium
measurement. Patients will take the intervention daily and will undergo repeat testing of all
of these measures at the end of a 3 month period. The primary endpoint will be change in
glucose tolerance, as measured by change in glucose area-under-the-curve (AUC) of a 3-hour
oral glucose tolerance test (OGTT). Secondary endpoints will include changes in fasting,
1-hour, and 2-hour post-challenge glucose levels, as well as measurements of insulin
secretion and insulin sensitivity as measures by the oral glucose minimal model method.(1)
The baseline data from this trial will allow us to quantify abnormalities in glucose
metabolism in African Americans with prediabetes/early diabetes and low-normal serum K. The
post-intervention data will provide estimates of the impact of K-supplements compared to no
supplements on these abnormalities. Data derived from the pilot study will be used in the
design of a larger scale, adequately powered clinical trial. This trial will also help to
assess the feasibility of recruiting this target population.
With this pilot trial, we will begin to determine whether or not K-supplements, an
inexpensive, well-tolerated, and simple intervention, could help to reduce diabetes risk
among African Americans.