Open Access Open Badges Study protocol

Effect of genetic testing for risk of type 2 diabetes mellitus on health behaviors and outcomes: study rationale, development and design

Alex H Cho1*, Ley A Killeya-Jones2, Julianne M O'Daniel3, Kensaku Kawamoto4, Patrick Gallagher5*, Susanne Haga6, Joseph E Lucas7, Gloria M Trujillo8, Scott V Joy9 and Geoffrey S Ginsburg10

Author Affiliations

1 Center for Personalized Medicine, Duke University, Department of Medicine, Duke University School of Medicine, DUMC Box 90141, Durham, NC, USA, 27710

2 Carolina Population Center, UNC-Chapel Hill, CB#8120 University Sq, 123 W Franklin Street, Room 304C, Chapel Hill, NC, USA, 27516

3 CGC Illumina, Inc., San Diego, CA, USA, 92121-1975

4 Department of Biomedical Informatics, University of Utah, 615 Arapeen Way, Suite 208 Salt

5 Center for health Services Research in Primary Care, Durham VA Medical Center, 508 Fulton St. (152), Durham, NC, USA, 27705

6 Center for Genomic Medicine, Institute for Genome Sciences & Policy, Department of Public Policy Studies Sanford School of Public Policy, Duke University, DUMC Box 90141, 304 Research Dr, North Bldg #228, Durham, NC, USA, 27708

7 Institute for Genome Sciences & Policy, Duke University, 101 Science Dr, Rm 2121, Durham, NC, USA, 27708

8 Department of Community and Family Medicine, Duke University School of Medicine, 2100 Erwin Rd, Marshall Pickens Building, DUMC Box 3886, Durham, NC, USA, 27710

9 Center for Personalized Medicine, Duke University, Department of Medicine, Duke University School of Medicine, DUMC Box 3228, Durham, NC, USA, 27710

10 Center for Personalized Medicine, Center for Genomic Medicine, Institute for Genome Sciences & Policy, Duke University, Departments of Medicine, Pathology, Duke University School of Medicine, 101 Science Dr, Rm 2111, DUMC Box 3382, Durham, NC, USA, 27708

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BMC Health Services Research 2012, 12:16  doi:10.1186/1472-6963-12-16

Published: 18 January 2012



Type 2 diabetes is a prevalent chronic condition globally that results in extensive morbidity, decreased quality of life, and increased health services utilization. Lifestyle changes can prevent the development of diabetes, but require patient engagement. Genetic risk testing might represent a new tool to increase patients' motivation for lifestyle changes. Here we describe the rationale, development, and design of a randomized controlled trial (RCT) assessing the clinical and personal utility of incorporating type 2 diabetes genetic risk testing into comprehensive diabetes risk assessments performed in a primary care setting.


Patients are recruited in the laboratory waiting areas of two primary care clinics and enrolled into one of three study arms. Those interested in genetic risk testing are randomized to receive either a standard risk assessment (SRA) for type 2 diabetes incorporating conventional risk factors

upfront disclosure of the results of genetic risk testing ("SRA+G" arm), or the SRA alone ("SRA" arm). Participants not interested in genetic risk testing will not receive the test, but will receive SRA (forming a third, "no-test" arm). Risk counseling is provided by clinic staff (not study staff external to the clinic). Fasting plasma glucose, insulin levels, body mass index (BMI), and waist circumference are measured at baseline and 12 months, as are patients' self-reported behavioral and emotional responses to diabetes risk information. Primary outcomes are changes in insulin resistance and BMI after 12 months; secondary outcomes include changes in diet patterns, physical activity, waist circumference, and perceived risk of developing diabetes.


The utility, feasibility, and efficacy of providing patients with genetic risk information for common chronic diseases in primary care remain unknown. The study described here will help to establish whether providing type 2 diabetes genetic risk information in a primary care setting can help improve patients' clinical outcomes, risk perceptions, and/or their engagement in healthy behavior change. In addition, study design features such as the use of existing clinic personnel for risk counseling could inform the future development and implementation of care models for the use of individual genetic risk information in primary care. NCT00849563

genetic information clinical utility; genetic testing; preventive health behavior; RCT protocol; risk perception; type 2 diabetes