The Effects of Potassium on Glucose Metabolism in African Americans
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|ClinicalTrials.gov Identifier: NCT02236598|
Recruitment Status : Completed
First Posted : September 10, 2014
Results First Posted : May 23, 2017
Last Update Posted : May 23, 2017
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.
|Condition or disease||Intervention/treatment||Phase|
|Borderline Hypokalemia||Drug: K+ supplement Drug: Placebo||Phase 2|
|Study Type :||Interventional (Clinical Trial)|
|Actual Enrollment :||61 participants|
|Intervention Model:||Parallel Assignment|
|Masking:||Triple (Participant, Investigator, Outcomes Assessor)|
|Official Title:||The Effects of Potassium on Glucose Metabolism in African Americans|
|Study Start Date :||January 2015|
|Actual Primary Completion Date :||February 29, 2016|
|Actual Study Completion Date :||February 29, 2016|
Experimental: K+ supplementation
K-supplement- Klor-Con® M10 is an immediately dispersing extended-release oral dosage form of potassium chloride containing 750 mg of microencapsulated potassium chloride, United States Pharmacopeia (USP) equivalent to 10 milliequivalent (mEq) of potassium in a tablet. Participants will be instructed to take two 10 mEq tablets twice daily in a blinded encapsulated form, for 3 months
Drug: K+ supplement
Placebo - An inert powdered placebo will be identically encapsulated as the Klor-Con intervention tablets to maintain blinding. Participants will be instructed to take two tablets twice daily in a blinded encapsulated form, for 3 months
Subjects will be instructed to take the pills
- 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).
- 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]).
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02236598
|United States, North Carolina|
|Duke University Medical Center|
|Durham, North Carolina, United States, 27710|
|Principal Investigator:||Ranee C Montgomery, MD||Duke University|