Genetic Testing for Type 2 Diabetes

US Department of Veterans Affairs (VA)

Status: Completed

Conditions: Diabetes Mellitus

Treatments: Behavioral: eye disease counseling; Behavioral: Conventional risk counseling; Genetic: genetic testing for type 2 diabetes

Study type: Interventional

Funder types: Other; Other U.S. Federal agency

Identifiers

NCT01060540

IBD 09-039

Details and patient eligibility

About

In this 6-month randomized, controlled trial, we examined whether providing participants with genetic test results and counseling regarding their risk for type 2 diabetes would motivate them to improve their health behaviors and lose weight to reduce their diabetes risk. We hypothesized that participants who received conventional diabetes counseling plus genetic test results and counseling would have at least 6 lb greater weight loss at 3 months than participants who received conventional diabetes counseling without genetic test results.

Full description

In this 6-month randomized, controlled trial, we evaluated the impact of genetic testing for type 2 diabetes on psychological, health behavior, and clinical outcomes. Eligibility criteria included age 21 to 65 years, overweight or obese (body mass index [BMI] >27 kg/m2), and no prior diagnosis of type 2 diabetes. At baseline, participants (N=601) had conventional risk factors assessed, including demographics, fasting plasma glucose (FPG), and family history. They also provided blood samples for genetic testing of TCF7L2, PPARG, and KCNJ11, three genes that confer elevated risk for development of type 2 diabetes. Participants were then randomized to receive conventional counseling plus control eye disease counseling (CR+EYE) or conventional counseling plus genetic test results (CR+G). Two to four weeks following the baseline visit, when the genetic test results were available, participants returned for a visit with a genetic counselor. All participants received conventional risk counseling based on their lifetime population risk, FPG results, and family history. Next, participants were informed of their randomization assignments; CR+EYE participants received counseling on eye diseases, whereas CR+G participants received genetic counseling. Then perceived risk, affect, self-efficacy, and readiness to change were assessed. All other outcomes were also assessed at 3 and 6 months.

Enrollment: 601 patients

Sex: All

Ages: 21 to 65 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• body mass index >27 kg/m2
• baseline fasting plasma glucose <=125 mg/dL

Exclusion criteria

• prior diagnosis of type 2 diabetes
• fasting plasma glucose >125 mg/dL on more than one occasion
• HbA1c > 7%
• taking diabetes medication
• actively losing weight
• enrolled in research study focusing on lifestyle changes
• unable to provide informed consent or answer survey questions unassisted
• residing in nursing home or receiving home health care
• active diagnosis of psychosis or dementia
• at least one error on 6-item cognitive screener

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Single Blind

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601 participants in 2 patient groups

CR+G

Experimental group

Description:

conventional risk counseling (lifetime risk, fasting plasma glucose, and family history) plus genetic testing for type 2 diabetes

Treatment:

Behavioral: Conventional risk counseling

Genetic: genetic testing for type 2 diabetes

CR+EYE

Active Comparator group

Description:

conventional risk counseling (lifetime risk, fasting plasma glucose, and family history) plus eye disease counseling

Treatment:

Behavioral: Conventional risk counseling

Behavioral: eye disease counseling