Low-Carbohydrate Dietary Pattern on Glycemic Outcomes Trial (ADEPT)

The proposed randomized controlled trial will test the effect of a low-carbohydrate diet on hemoglobin A1c among individuals with elevated hemoglobin A1c that are within the range of prediabetes or diabetes. Results may provide evidence about the role of carbohydrate restriction in individuals with or at high risk of type 2 diabetes.

Study Overview

• Status: Completed
• Conditions: Hyperglycemia; Endocrine System Diseases; Diabetes; PreDiabetes; Glucose Intolerance; Diet Modification; Metabolic Disease; Glucose Metabolism Disorders (Including Diabetes Mellitus)
• Intervention / Treatment: Behavioral: Low-Carbohydrate Diet

Detailed Description

In the short-term, among patients with type 2 diabetes, low-to-moderate carbohydrate diets have a greater glucose-lowering effect than do high-carbohydrate diets. However, compared with usual diet, the effect of a behavioral intervention promoting a low-carbohydrate/high-unsaturated fat and high-protein dietary pattern among individuals with prediabetes or untreated type 2 diabetes is not well understood.

The overall goal of this randomized controlled trial is to study the effect of a behavioral intervention promoting a low-carbohydrate/high-unsaturated fat and high-protein dietary pattern compared with usual diet on hemoglobin A1c (HbA1c) and other metabolic risk factors among individuals with or at high risk of diabetes (HbA1c 6.0-6.9%).

A total of 150 participants with HbA1c 6.0-6.9% will be recruited and randomly assigned to either a 6-month behavioral modification program designed to reduce carbohydrate intake (initial target <40 g digestible carbohydrates, final target <60 g digestible carbohydrates) or to usual diet in a 1:1 randomization ratio.

The primary outcome will be the difference between the active intervention and control groups for change in HbA1c from baseline to 6 months. Secondary outcomes will be fasting glucose, systolic blood pressure, total-to-high-density lipoprotein-cholesterol ratio, and body weight.

Findings from this study may provide evidence about the role of carbohydrate restriction in individuals with or at high risk of type 2 diabetes.

• Study Type: Interventional
• Enrollment (Actual): 150
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Louisiana
    • New Orleans, Louisiana, United States, 70112
      • Tulane Office of Health Research

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 40 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Men or women ages 40 to 70 years
• HbA1c 6.0-6.9%
• Willing and able to provide informed consent

Exclusion Criteria:

• Diagnosed type 1 diabetes mellitus
• Use of agents affecting glycemic control (medications for diabetes, oral glucocorticoids) within the past three months prior to enrollment
• Medical condition in which low-carbohydrate diet may not be advised: estimated glomerular filtration rate (eGFR) ≤45 mL/min/1.73 m²; self-report of liver disease due to hepatitis or alcohol; osteoporosis; untreated thyroid disease; gout; cancer (other than non-melanoma skin cancer) requiring treatment in the past year, unless prognosis is excellent
• Factors that may affect HbA1c: hemoglobin <11 mg/dL (cutpoint for moderate-to-severe anemia, which could lead to falsely elevated or lowered HbA1c); recent blood donation or blood transfusion (self-report, past 4 months); human immunodeficiency virus (self-report)
• Self-reported history of intensive care unit stay due to Coronavirus Disease 2019 (COVID-19) in the past three months, as severe COVID-19 may affect blood glucose levels
• Allergies to nuts
• For women, current pregnancy, breastfeeding, or plans to become pregnant during the study
• Consumption of ≥21 alcoholic drinks per week or consumption of ≥6 drinks per occasion
• Current or planned residence making it difficult to meet trial requirements (due to distance from study site and/or challenges regularly traveling to site)
• Current participation in another lifestyle intervention trial or a pharmaceutical trial
• Participation of another household member in the study; employees or persons living with employees of the study
• Other concerns regarding ability to meet trial requirements, at the discretion of the principal investigator or study coordinator

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Low-Carbohydrate Diet; Behavioral modification to reduce carbohydrate consumption. Target <40 g net carbohydrates per day for first 3 months; <60 g net carbohydrates per day for months 4 onwards. The intervention will consist of 4 weekly individual counseling sessions, followed by 4 group sessions held every other week, with phone follow-ups in between group sessions. For the last 3 months of the study, there will be 3 monthly group sessions and 3 telephone follow-ups. At baseline, participants will receive written information with standard physical activity recommendations.	Behavioral: Low-Carbohydrate Diet; Behavioral modification to reduce carbohydrate consumption. Target <40 g net carbohydrates per day for first 3 months; <60 g net carbohydrates per day for months 4 onwards. The intervention will consist of 4 weekly individual counseling sessions, followed by 4 group sessions held every other week, with phone follow-ups in between group sessions. For the last 3 months of the study, there will be 3 monthly group sessions and 3 telephone follow-ups. At baseline, participants will receive written information with standard physical activity recommendations.
No Intervention: Usual Diet; No dietary intervention. At baseline, participants will receive written information with standard dietary advice and standard physical activity recommendations.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Hemoglobin A1c	6-month change in Hemoglobin A1c comparing low-carbohydrate arm with usual diet arm	Baseline and six months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Fasting Plasma Glucose	6-month change in fasting plasma glucose comparing low-carbohydrate arm with usual diet arm	Baseline and six months
Change in Systolic Blood Pressure	6-month change in systolic blood pressure comparing low-carbohydrate arm with usual diet arm	Baseline and six months
Change in Total-to-HDL-cholesterol Ratio	6-month change in total-to-HDL-cholesterol ratio comparing low-carbohydrate arm with usual diet arm	Baseline and six months
Change in Body Weight	6-month change in body weight comparing low-carbohydrate arm with usual diet arm	Baseline and six months

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Insulin	6-month change in fasting insulin comparing low-carbohydrate arm with usual diet arm	Baseline and six months
Change in Homeostasis Model Assessment of Insulin Resistance (HOMA-IR)	6-month change in HOMA-IR comparing low-carbohydrate arm with usual diet arm. HOMA-IR was calculated as fasting insulin (μIU/mL) x fasting glucose (mmol/L)/22.5.	Baseline and six months
Change in Diastolic Blood Pressure	6-month change in diastolic blood pressure comparing low-carbohydrate arm with usual diet arm	Baseline and six months
Change in Waist Circumference	6-month change in waist circumference comparing low-carbohydrate arm with usual diet arm	Baseline and six months
Change in Estimated Atherosclerotic Cardiovascular Disease Risk	6-month change in estimated 10-year atherosclerotic cardiovascular disease risk comparing low-carbohydrate arm with usual diet arm. The estimated 10-year cardiovascular disease risk was assessed by 2013 American College of Cardiology/American Heart Association Atherosclerotic Cardiovascular Disease Risk Score, known as the Pooled Cohort Equations. The Pooled Cohort Equations estimate the 10-year primary risk of ASCVD (atherosclerotic cardiovascular disease) among patients without pre-existing cardiovascular disease who are between 40 and 79 years of age. Variables included in the risk score include: gender, age, race, total cholesterol, HDL cholesterol, systolic blood pressure, treatment for blood pressure, diabetes, and smoking status. Reference: Goff DC, Lloyd-Jones DM et al. 2013 ACC/AHA guideline on the assessment of cardiovascular risk: A report of the American college of cardiology/American heart association task force on practice guidelines. Vol. 129, Circulation. 2014.	Baseline and six months

Collaborators and Investigators

• Sponsor: Tulane University School of Public Health and Tropical Medicine
• Collaborators: National Institute of General Medical Sciences (NIGMS)

Publications and helpful links

General Publications

• Dorans KS, Bazzano LA, Qi L, He H, Chen J, Appel LJ, Chen CS, Hsieh MH, Hu FB, Mills KT, Nguyen BT, O'Brien MJ, Samet JM, Uwaifo GI, He J. Effects of a Low-Carbohydrate Dietary Intervention on Hemoglobin A1c: A Randomized Clinical Trial. JAMA Netw Open. 2022 Oct 3;5(10):e2238645. doi: 10.1001/jamanetworkopen.2022.38645.
• Dorans KS, Bazzano LA, Qi L, He H, Appel LJ, Samet JM, Chen J, Mills KT, Nguyen BT, O'Brien MJ, Uwaifo GI, He J. Low-carbohydrate dietary pattern on glycemic outcomes trial (ADEPT) among individuals with elevated hemoglobin A1c: study protocol for a randomized controlled trial. Trials. 2021 Feb 1;22(1):108. doi: 10.1186/s13063-020-05001-x.

Study record dates

Study Major Dates

• Study Start (Actual): September 25, 2018
• Primary Completion (Actual): June 21, 2021
• Study Completion (Actual): June 21, 2021

Study Registration Dates

• First Submitted: September 14, 2018
• First Submitted That Met QC Criteria: September 16, 2018
• First Posted (Actual): September 18, 2018

Study Record Updates

• Last Update Posted (Actual): March 1, 2023
• Last Update Submitted That Met QC Criteria: January 31, 2023
• Last Verified: January 1, 2023

More Information

Terms related to this study

• Keywords: Diabetes; Prediabetes; Low-Carbohydrate Diet
• Additional Relevant MeSH Terms: Hyperglycemia; Diabetes Mellitus; Prediabetic State; Glucose Intolerance; Endocrine System Diseases; Metabolic Diseases; Glucose Metabolism Disorders
• Other Study ID Numbers: 2018-053; P20GM109036 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No