Type 1 Together: A Multisite RCT of a Peer Mentor Program for Teens with Type 1 Diabetes - PROJECT SUMMARY Fewer than 1 in 5 adolescents with type 1 diabetes (T1D) achieve the glycemic levels recommended by the American Diabetes Association, increasing their risk for acute and long-term health complications. Continuous glucose monitoring systems (CGM) can improve the physical and mental health of youth with T1D, but only if worn consistently (≥ 80% of the time). However, adolescents are less likely than children and young adults to wear CGM consistently. Barriers to using CGM align with the three domains of Social Cognitive Theory, a widely used theory to understand influences on individuals’ health behaviors: personal (e.g., perceived benefits and burdens of CGM, self-efficacy to manage diabetes), behavioral (e.g., family involvement, adherence), and environmental (e.g., cost, insurance). Unfortunately, rigorously tested interventions to bolster consistent use of CGM are lacking. Type 1 Together is an intervention that was co-developed in partnership with youth with T1D and their families. Type 1 Together combines peer mentoring and support from a community health worker to target personal, behavioral, and environmental barriers to consistently using CGM. Data from a pilot randomized controlled trial (RCT) suggests that Type 1 Together is acceptable, feasible, and may improve glycemic levels, CGM wear time, and mental health outcomes among adolescents with T1D. The current proposal extends this line of research and proposes to rigorously evaluate the efficacy of Type 1 Together in a multisite RCT. Adolescent-caregiver dyads (n=180) will be recruited from three sites (Nemours – Delaware, Nemours – Orlando, University of Tennessee – Memphis) and randomized 1:1 to Type 1 Together or a 6month waitlist control. During the intervention phase, families will meet at least monthly with a peer mentor family and a community health worker. We will then evaluate the efficacy of Type 1 Together in improving health and psychosocial outcomes (Aim 1) and the effect of Type 1 Together on Social Cognitive Theory constructs (Aim 2). While the multi-site RCT is underway, we will also use a mixed-methods approach informed by the Practical, Robust Implementation and Sustainability Model to identify strategies to implement Type 1 Together as part of routine clinical care. Upon completion of this project, we will have data regarding the efficacy of Type 1 Together (Aim 1), elucidate potential mechanisms underlying the intervention (Aim 2), and have strategies to overcome potential barriers to implementing Type 1 Together more broadly (Aim 3).