Enhancing the Diabetes Prevention Program to promote weight loss among non-responders in a community based lifestyle intervention

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PROJECT SUMMARY Obesity is the number one and most preventable Type 2 diabetes (T2D) risk factor yet despite a $20 billion annual expenditure on diet and weight loss efforts, 87% of US adults are overweight or obese. Disparities also persist, as Non-Hispanic Black adults have a higher obesity prevalence (46.8%) than non-Hispanic Whites (37.9%) and suffer higher rates of Type 2 diabetes (T2D). The Diabetes Prevention Program (DPP) lifestyle intervention (LI) demonstrated the clinical benefits of lifestyle intervention and garnered the Center for Disease Control (CDC) endorsement as the gold standard LI program for US adults. Reimbursable by the Center for Medicare and Medicaid Services (CMS), the DPP LI is currently disseminated nationally and the national DPP. While the DPP LI is effective, critical populations don’t achieve clinically significant weight loss in the current group-based translation paradigm. This is particularly true for Black DPP participants, who show the lowest adjusted percent weight loss across (3.2%) among all racial/ethnic groups. A lack of weight loss in the early weeks of intervention is a known predictor of post-treatment outcomes and continues to be a major barrier to weight loss for Black participants. Additional research on early intervention, with a focus on populations that experience disparities, is urgently needed as the new CMS payment structure (based on weight loss metrics) may further limit access to the DPP for Blacks. This project proposes a cluster randomized control trial with 500 Black participants who are nested in 20 community sites, primarily churches. Trained community health workers will deliver a group-based, 6-month long DPP Group Lifestyle Balance (DPP-GLB) over 18 sessions and nonresponders will be identified at four weeks. Nonresponders in the intervention group only will receive weekly telephone support from the CHWs to provide individual-level enhanced treatment to help them overcome barriers to adherence to the program goals. These activities will meet the following Specific Aims: 1) To evaluate differences over time in the primary outcome of weight, and secondary outcomes (i.e., physical activity level, blood pressure, and dietary behaviors) between nonresponders in the intervention group compared to nonresponders in the active control group. 2) To examine potential mediators (social support, self-efficacy, motivation, stress) and moderators (age, sex, socioeconomic status) of the relationship between treatment group and early weight loss response in the both nonresponders and responders.3) To evaluate the cost of the intervention arm by comparing the incremental cost and weight loss with the active control arm. Outcome measures include weight (primary); secondary outcomes include blood pressure, physical activity, dietary behaviors, mediation and moderator effects and cost. If found to efficacious, the enhanced strategies for nonresponders could be standardized as a supplement for use with the national DPP and may be supported by current DPP payers.