The intervention seeks to address the need to test in routine primary care evidence-based approaches to increase uptake, engagement, and maintenance of healthy behaviors necessary to decrease progression to diabetes among primary care patients with prediabetes, especially low-income and racial and ethnic minority adults with prediabetes. The study will conduct a parallel, two-armed, randomized controlled pragmatic clinical trial including adults with prediabetes at two primary care centers in two different health systems: Kaiser Permanente Northern California and the University of Michigan Health System. Each health system received IRB approval from its own IRB to accommodate site-specific nuances in its implementation. The trial will evaluate whether adding a 12-month predominantly telephone-based volunteer peer support program (UPSTART) to health care provider counseling and referral to diabetes prevention programs leads to greater improvements in A1c, the weight loss, and waist circumference than health care provider counseling and referral alone (Aim 1). The study will also compare differences in reported physical activity, diet, and enrollment and engagement in diabetes prevention programs as potential mediators as well as autonomous motivation, behavior-specific self-efficacy, patient activation, and perceived support; and moderators such as health literacy (Aim 2). To enhance adoption of the intervention by the two study health systems and dissemination to other health systems if effective, the study will evaluate costs and use an integrated RE-AIM and Consolidated Framework for Implementation Research (CFIR) framework to evaluate processes of intervention implementation in the two primary care settings (Aim 3). The study duration will be 5 years, to allow for peer supporter and patient recruitment, completion of the 12-month program, and assessment of outcomes at 6 months and at 12 months.

The study will use mixed methods-i.e., the collection, analysis, and combining of both quantitative and qualitative data-to investigate elements important for implementation and dissemination. The study will gather data on how peer supporters, primary care clinic staff, and patients experience the intervention and how the experiences of participants together with the trial's results suggest the study should modify the intervention. Using this approach, the study aim to ensure that the intervention has the greatest possible likelihood of adoption in both UMHS and KPNC health systems should the study find it has positive effects on processes and outcomes of care. The UPSTART intervention is designed for peers to interact and provide support in a way that is autonomy supportive with the goal of enhancing autonomous motivation and self-efficacy for healthy behaviors. The study will hold periodic initial trainings for new peer supporters over the study period. In addition, peer supporters will receive: 1) routine, structured check-ins that will include monthly peer support group meetings (with option to call in) to allow exchange; 2) back-up support: offering peer supporters contact information for staff who they can call; and 3) continuing education and booster training at the monthly group meetings to enrich their skill sets and knowledge.

The peer supporters were included in the total number of participant numbers for the trial and in the intervention arm in the study flow portion of this record because they were consented. Demographic characteristics of the peer supporters are also reported. However, they were not randomized; they were recruited to deliver the intervention to recruited participants with prediabetes whose outcomes we aimed to improve through the delivered intervention. The peer supporters' involvement was to deliver the intervention to the participants who were randomized to either receive the peer support intervention or to enhanced usual care. The study consented the peer supporters because they completed surveys at three time points; the intent was to look at whether delivering the intervention affected the peer supporters' own reported behaviors as exploratory only. There was and is no intention to compare coach data to primary, secondary, or any other outcome measures of the randomized participants in the trial.

During the trial, another primary care center within the University of Michigan Health System was added. Because this center was within the University of Michigan Health System, and all contact information was identical, there was no reason to add another participating site.