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The Effects of Potassium on Glucose Metabolism in African Americans

Primary Purpose

Borderline Hypokalemia

Status
Completed
Phase
Phase 2
Locations
United States
Study Type
Interventional
Intervention
K+ supplement
Placebo
Sponsored by
Duke University
About
Eligibility
Locations
Arms
Outcomes
Full info

About this trial

This is an interventional treatment trial for Borderline Hypokalemia focused on measuring borderline hypokalemia, glucose tolerance, insulin secretion, insulin sensitivity, fasting glucose, African American

Eligibility Criteria

30 Years - undefined (Adult, Older Adult)All SexesDoes not accept healthy volunteers

Inclusion Criteria:

To be eligible for inclusion in the study the following enrollment criteria must be met:

  1. Participants must be 30 years of age or older.
  2. They must have a diagnosis of prediabetes defined as a hemoglobin A1c between 5.7-6.5% measured at the initial screening visit.
  3. They must have a serum K+ of 3.3-4.0 mEq/L on 2 occasions, within a 18 month period, including at initial screening visit. If subject is just outside range for inclusion, PI may offer the subject the option to repeat their screening serum K+ measurement.
  4. The participant must be willing and capable of providing written informed consent.
  5. The participant must be available for follow-up and must at minimum have telephone access.
  6. Participants must be able to read/understand English.

Exclusion Criteria:

  • Participants must not have any of the following:

    1. Participants must not have evidence of chronic kidney disease with an estimated Glomerular Filtration Rate (eGFR) < 60ml/min. All patients will be screened for eGFR at the enrollment visit.
    2. Participants must not have evidence of diabetes mellitus requiring treatment with medications prior to screening visit. The cannot have a random or post-challenge glucose ≥ 200mg/dl (from prior labs), A1c level ≥ 6.5% (from prior labs), prior physician diagnosis, or use of anti-diabetic medications. If participants have glucose levels in the diabetic range at screening visit, they will be eligible to continue in study as long as glucose levels are not > 200 mg/dl.
    3. Participants must not have a history of endoscopy-verified peptic ulcer disease with past history of either gastric or duodenal ulcer.
    4. Participants must not have evidence of cardiac arrhythmias, unstable angina or cardiac event within 6 months, congestive heart failure, or other conditions that might impact follow-up, based on the discretion of the principal investigator.
    5. Participants must not be pregnant or intend to get pregnant during the study period. The study intervention is safe for pregnant women, so serum pregnancy screening is not indicated; however, pregnant women are excluded because pregnancy affects glucose homeostasis, which will bias primary outcome measurement and damage scientific validity of the study.

Sites / Locations

  • Duke University Medical Center

Arms of the Study

Arm 1

Arm 2

Arm Type

Experimental

Experimental

Arm Label

K+ supplementation

Placebo

Arm Description

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

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

Outcomes

Primary Outcome Measures

Change in Glucose Tolerance as Measured by Area-under-the-curve
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).

Secondary Outcome Measures

Changes in Fasting, 1-hour, and 2-hour Post-challenge Glucose Levels in mg/dL
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)
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
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]).

Full Information

First Posted
September 8, 2014
Last Updated
April 19, 2017
Sponsor
Duke University
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1. Study Identification

Unique Protocol Identification Number
NCT02236598
Brief Title
The Effects of Potassium on Glucose Metabolism in African Americans
Official Title
The Effects of Potassium on Glucose Metabolism in African Americans
Study Type
Interventional

2. Study Status

Record Verification Date
April 2017
Overall Recruitment Status
Completed
Study Start Date
January 2015 (undefined)
Primary Completion Date
February 29, 2016 (Actual)
Study Completion Date
February 29, 2016 (Actual)

3. Sponsor/Collaborators

Responsible Party, by Official Title
Sponsor
Name of the Sponsor
Duke University

4. Oversight

Data Monitoring Committee
No

5. Study Description

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 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.

6. Conditions and Keywords

Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
Borderline Hypokalemia
Keywords
borderline hypokalemia, glucose tolerance, insulin secretion, insulin sensitivity, fasting glucose, African American

7. Study Design

Primary Purpose
Treatment
Study Phase
Phase 2
Interventional Study Model
Parallel Assignment
Masking
ParticipantInvestigatorOutcomes Assessor
Allocation
Randomized
Enrollment
61 (Actual)

8. Arms, Groups, and Interventions

Arm Title
K+ supplementation
Arm Type
Experimental
Arm Description
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
Arm Title
Placebo
Arm Type
Experimental
Arm Description
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
Intervention Type
Drug
Intervention Name(s)
K+ supplement
Intervention Type
Drug
Intervention Name(s)
Placebo
Primary Outcome Measure Information:
Title
Change in Glucose Tolerance as Measured by Area-under-the-curve
Description
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).
Time Frame
Baseline to 3 months
Secondary Outcome Measure Information:
Title
Changes in Fasting, 1-hour, and 2-hour Post-challenge Glucose Levels in mg/dL
Description
Changes in fasting, 1-hour, and 2-hour post-challenge glucose levels in mg/dL
Time Frame
Baseline to 3 months
Title
Changes in Insulin Secretion as Measured by 2-hour Insulin Area-under-the-curve (AUC)
Description
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.
Time Frame
Baseline to 3 months
Title
Changes in Insulin Sensitivity
Description
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]).
Time Frame
Baseline to 3 months

10. Eligibility

Sex
All
Minimum Age & Unit of Time
30 Years
Accepts Healthy Volunteers
No
Eligibility Criteria
Inclusion Criteria: To be eligible for inclusion in the study the following enrollment criteria must be met: Participants must be 30 years of age or older. They must have a diagnosis of prediabetes defined as a hemoglobin A1c between 5.7-6.5% measured at the initial screening visit. They must have a serum K+ of 3.3-4.0 mEq/L on 2 occasions, within a 18 month period, including at initial screening visit. If subject is just outside range for inclusion, PI may offer the subject the option to repeat their screening serum K+ measurement. The participant must be willing and capable of providing written informed consent. The participant must be available for follow-up and must at minimum have telephone access. Participants must be able to read/understand English. Exclusion Criteria: Participants must not have any of the following: Participants must not have evidence of chronic kidney disease with an estimated Glomerular Filtration Rate (eGFR) < 60ml/min. All patients will be screened for eGFR at the enrollment visit. Participants must not have evidence of diabetes mellitus requiring treatment with medications prior to screening visit. The cannot have a random or post-challenge glucose ≥ 200mg/dl (from prior labs), A1c level ≥ 6.5% (from prior labs), prior physician diagnosis, or use of anti-diabetic medications. If participants have glucose levels in the diabetic range at screening visit, they will be eligible to continue in study as long as glucose levels are not > 200 mg/dl. Participants must not have a history of endoscopy-verified peptic ulcer disease with past history of either gastric or duodenal ulcer. Participants must not have evidence of cardiac arrhythmias, unstable angina or cardiac event within 6 months, congestive heart failure, or other conditions that might impact follow-up, based on the discretion of the principal investigator. Participants must not be pregnant or intend to get pregnant during the study period. The study intervention is safe for pregnant women, so serum pregnancy screening is not indicated; however, pregnant women are excluded because pregnancy affects glucose homeostasis, which will bias primary outcome measurement and damage scientific validity of the study.
Overall Study Officials:
First Name & Middle Initial & Last Name & Degree
Ranee C Montgomery, MD
Organizational Affiliation
Duke University
Official's Role
Principal Investigator
Facility Information:
Facility Name
Duke University Medical Center
City
Durham
State/Province
North Carolina
ZIP/Postal Code
27710
Country
United States

12. IPD Sharing Statement

Citations:
PubMed Identifier
32556595
Citation
Chatterjee R, Davenport CA, Kwee L, D'Alessio D, Svetkey LP, Lin PH, Slentz CA, Ilkayeva O, Johnson J, Edelman D, Shah SH. Preliminary evidence of effects of potassium chloride on a metabolomic path to diabetes and cardiovascular disease. Metabolomics. 2020 Jun 18;16(7):75. doi: 10.1007/s11306-020-01696-w.
Results Reference
derived
PubMed Identifier
29092881
Citation
Chatterjee R, Slentz C, Davenport CA, Johnson J, Lin PH, Muehlbauer M, D'Alessio D, Svetkey LP, Edelman D. Effects of potassium supplements on glucose metabolism in African Americans with prediabetes: a pilot trial. Am J Clin Nutr. 2017 Dec;106(6):1431-1438. doi: 10.3945/ajcn.117.161570. Epub 2017 Nov 1.
Results Reference
derived

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The Effects of Potassium on Glucose Metabolism in African Americans

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