Real-time Engagement for Learning to Effectively Control Type 2 Diabetes

This is a clinical trial that includes a run-in period, a 90 day micro-randomized trial, and a 90-day observational period. The goal of this study is to evaluate whether providing paired real time glycemic and health behavior data in a smartphone app leads to better glycemic control among adolescents and young adults with T2D. Glycemic control will be monitored using Continuous Glucose Monitors (CGM), and health behavior data will be collected via a Fitbit activity tracker and a research app (Healthmine). Participants will be prompted to view and reflect on glycemic trends and health behavior data (Fitbit data, logging of diet and medication adherence) during the 90-day micro-randomized trial period, then observed for ongoing use of the Healthmine app and engagement with CGM in the following 90-day observation period.

The objective of REFLECT2D (Real-time Engagement For Learning to Effectively Control Type 2 Diabetes) is to evaluate whether pairing real-time glycemic and health behavior data leads to improved glycemic control among adolescents and young adults with type 2 diabetes. Participants will use a mobile app that integrates continuous glucose monitor data, Fitbit activity tracker data, and diet logging, with the aim of increasing capability to interpret glycemic data (including impacts of physical activity and dietary intake), providing opportunity to plan and implement behavior change, and increasing motivation to engage in health behaviors. After a session with a Registered Dietitian and Diabetes Educator who will support participants in forming diet and activity goals, a 90-day micro-randomized trial (MRT) period will involve once daily randomization of each participant to: 1) physical-activity focused prompt, 2) dietary intake-focused prompt, or 3) no prompt. Prompts will include reviews of glycemic trends in the past 24 hours (e.g., periods of hyperglycemia, max glucose) and will ask participants to use visual summaries of activity or diet and glucose to reflect on and revise their behavioral management goals as needed. After the MRT, a 90-day observation period without prompts but with ongoing availability of continuous glucose monitor data, Fitbit, and Healthmine app will examine persistence of glycemic and behavior changes. In addition to daily micro-randomization, participants will be randomized 1:1 at study start to proactive outreach from the study team in the case of 3 or more days of missing data, versus no outreach for missing data.

Inclusion Criteria: * type 2 diabetes: negative diabetes autoantibodies, no suspicion for monogenic diabetes * HbA1c ≥7.0%, stable medication use * HbA1c 6.0-6.9% without short-acting insulin, any other stable diabetes medication use * English-speaking (app in English) Exclusion Criteria: * Current pregnancy * Hydroxyurea use (CGM sensor inaccuracies) * Cognitive impairment or severe psychiatric condition that could interfere with participation in behavioral intervention for diabetes self-management * Current or previously diagnosed eating disorder