Determinants, implementation strategies, and mechanisms of the 4T Program

= 451). Based on promising single center experience, we examine the potential for program scaling to the T1D Exchange Quality Improvement (T1DX-QI) Collaborative using an implementation science approach. We used the Simplified Implementation Logic Model to identify contextual determinants of implementation success. Then, we described the connections between the implementation support strategies used in 4T to address the contextual determinants and barriers to program reach to youth with T1D and provider adoption. We hypothesized mechanisms linking barriers and strategies to effectiveness and implementation outcomes. Limited clinician time was identified as a major barrier to program success. Several targeted strategies were used to address this, including the creation of the Timely Interventions for Diabetes Excellence (TIDE) clinical decision support tool early in the program and ongoing refinement of the tool. After clinical effectiveness of the 4T Program was established, the next phase focused on further allocating clinician monitoring to participants who would benefit the most. Additionally, cost to the family participants, cost to the clinic, and interest-holder engagement were other determinants addressed by the program strategies. This implementation evaluation informed connections between determinants, support strategies, mechanisms, and outcomes of the 4T Program. This enabled a more precise design in preparation to scale the program across a national network of pediatric diabetes clinics in the T1DX-QI.