ADEPT: Low-Carbohydrate Dietary Pattern on Glycemic Outcomes Trial

Sponsor

Tulane University School of Public Health and Tropical Medicine (Other)

Overall Status

Completed

CT.gov ID

NCT03675360

Collaborator

National Institute of General Medical Sciences (NIGMS) (NIH)

150

Enrollment

Location

Arms

32.9

Actual Duration (Months)

4.6

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

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.

Condition or Disease	Intervention/Treatment	Phase
Diabetes PreDiabetes Metabolic Disease Hyperglycemia Diet Modification Glucose Intolerance Glucose Metabolism Disorders (Including Diabetes Mellitus) Endocrine System Diseases	Behavioral: Low-Carbohydrate Diet	N/A

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 Design

Study Type:

Interventional

Actual Enrollment :

150 participants

Allocation:

Randomized

Intervention Model:

Parallel Assignment

Masking:

Double (Investigator, Outcomes Assessor)

Primary Purpose:

Prevention

Official Title:

Low-Carbohydrate Dietary Pattern on Glycemic Outcomes Trial

Actual Study Start Date :

Sep 25, 2018

Actual Primary Completion Date :

Jun 21, 2021

Actual Study Completion Date :

Jun 21, 2021

Arms and Interventions

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.

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

No Intervention: Usual Diet

No dietary intervention. At baseline, participants will receive written information with standard dietary advice and standard physical activity recommendations.

Outcome Measures

Primary Outcome Measures

Change in Hemoglobin A1c [Baseline and six months]

Secondary Outcome Measures

Change in fasting plasma glucose [Baseline and six months]
Change in systolic blood pressure [Baseline and six months]
Change in total-to-HDL-cholesterol ratio [Baseline and six months]
Change in body weight [Baseline and six months]

Other Outcome Measures

Change in insulin [Baseline and six months]
Change in homeostasis model assessment of insulin resistance (HOMA-IR) [Baseline and six months]
Change in diastolic blood pressure [Baseline and six months]
Change in waist circumference [Baseline and six months]
Change in estimated cardiovascular disease risk [Baseline and six months]
Based on 10-year cardiovascular disease risk assessed by 2013 American College of Cardiology/American Heart Association Atherosclerotic Cardiovascular Disease Risk Score

Eligibility Criteria

Criteria

Ages Eligible for Study:

40 Years to 70 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Yes

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