Clinical Trial: The Effects of Potassium on Glucose Metabolism in African Americans

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: The Effects of Potassium on Glucose Metabolism in African Americans

Brief 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 da

Detailed Summary:
Sponsor: Duke University

Current Primary Outcome: Change in Glucose Tolerance as Measured by Area-under-the-curve [ Time Frame: Baseline to 3 months ]

Change in glucose tolerance, as measured by change in glucose area-under-the-curve (Area Under the Curve (AUC) - measured via the trapezoidal method) of 2 hours from the 3-hour Oral Glucose Tolerance Test (OGTT).


Original Primary Outcome: Change in Glucose Tolerance [ Time Frame: 3 months ]

Change in glucose tolerance, as measured by change in glucose area-under-the-curve (AUC) of a 3-hour oral glucose tolerance test (OGTT).


Current Secondary Outcome:

  • Changes in Fasting, 1-hour, and 2-hour Post-challenge Glucose Levels in mg/dL [ Time Frame: Baseline to 3 months ]
    Changes in fasting, 1-hour, and 2-hour post-challenge glucose levels in mg/dL
  • Changes in Insulin Secretion as Measured by 2-hour Insulin Area-under-the-curve (AUC) [ Time Frame: Baseline to 3 months ]
    Changes in Insulin Secretion as measured by 2-hour insulin area-under-the-curve (AUC - measured via the trapezoidal method) of 2 hours from the 3-hour OGTT.
  • Changes in Insulin Sensitivity [ Time Frame: Baseline to 3 months ]
    Matsuda Insulin Sensitivity Index was calculated as: 10,000 / square root of [fasting glucose x fasting insulin x mean glucose x mean insulin during Oral Glucose Tolerance Test]).


Original Secondary Outcome:

  • Changes in fasting, 1-hour, and 2-hour post-challenge glucose levels [ Time Frame: 3 months ]
    Changes in fasting, 1-hour, and 2-hour post-challenge glucose levels
  • Changes in Insulin Secretion [ Time Frame: 3 months ]
    Changes in insulin secretion as measured by OGTT Minimal Model Analyses Method of Cobelli et al, Diabetes 63: 1203-1213, 2014, using plasma c-peptide & insulin values obtained at 0, 10, 20, 30, 60, 90, 120, 180 minutes after a standard 75 gram oral glucose challenge.
  • Changes in Insulin Sensitivity [ Time Frame: 3 months ]
    Changes in insulin sensitivity by Oral glucose tolerance test Minimal Model analyses of Cobelli et al., Diabetes 63: 1203-1213, 2014


Information By: Duke University

Dates:
Date Received: September 8, 2014
Date Started: January 2015
Date Completion:
Last Updated: April 19, 2017
Last Verified: April 2017