Glucose, Understanding, Integrated Digital Health, and Engagement (GUIDE) Study

Participants will complete a total of three study visits: a baseline visit (which includes consent, screening, and enrollment procedures), a 16-week follow-up visit, and a 32-week follow-up visit. Each study visit is expected to last approximately 30 minutes. In addition, participants will complete study surveys throughout the study period, which are expected to require approximately 30-40 minutes per survey. Depending on study group assignment, participants may also use study devices and mobile applications to track health behaviors and/or participate in telehealth visits with a healthcare provider. The frequency and duration of these activities will vary by study group.

• Integrated Digital Health (IDH) platform (Behavioral): CGM, wearable for physical activity and sleep, food scan/log
• Provider engagement (Behavioral): Weekly feedback through the IDH platform plus monthly video calls

Primary outcomes

• Mean Hemoglobin A1c (HbA1c) [Baseline, 16 weeks and 32 weeks]: HbA1c in milligrams per deciliter (mg/dL) will be measured using blood testing conducted according to the standardized procedures of the National Glycohemoglobin Standardization Program (NGSP).
• Mean Glucose Variability (Coefficient of Variation [%CV]) [Baseline, 16 weeks and 32 weeks]: Glucose variability will be derived from continuous glucose monitoring (CGM) data and calculated as the coefficient of variation (CV = standard deviation/mean glucose × 100). This measure reflects intra- and inter-day fluctuations in glucose levels. Consistent with consensus recommendations, a CV ≤36% is considered stable glucose variability.
• Percentage of glucose readings with Time in Range (TIR) [Baseline, 16 weeks and 32 weeks]: TIR will be derived from CGM data and calculated as the percentage of glucose readings and time per day within the target glucose range of 70-180 mg/dL (3.9-10.0 mmol/L). Consistent with consensus recommendations, a TIR ≥70% is considered an indicator of optimal glycemic management.

Secondary outcomes

• Mean score Revised Summary of Diabetes Self-Care Activities (SDSCA) [Baseline, 16 weeks and 32 weeks]: 12-item validated measure evaluating adherence to diabetes self-care behaviors, including diet, physical activity, blood glucose monitoring, and medication adherence. Total score range 0-7 with higher scores indicating more adherence.
• Mean score Diabetes Management Self-Efficacy Scale [Baseline, 16 weeks and 32 weeks]: 20-item validated instrument measuring participants' confidence in their ability to manage diabetes-related tasks and challenges. Total score range 1-5 with higher scores indicating a greater level of self-efficacy.
• Mean score Diabetes Distress Scale [Baseline, 16 weeks and 32 weeks]: 17-item scale which assesses distress associated with diabetes management, healthcare providers, emotional burden, and interpersonal concerns. Total score range 1-6 with higher scores indicating more distress.
• Mean score Diabetes Quality of Life Brief Clinical Inventory [Baseline, 16 weeks and 32 weeks]: 15-item validated instrument evaluating the impact of diabetes on physical, emotional, and social well-being. Total score range 1-5 with higher scores indicating a more negative perspective of the condition.

Sex: All, ages: 18 Years to 70 Years

Inclusion Criteria:

* diagnosis of T2D for at least one year
* recent 3 month-HbA1c, 8-11%
* ownership of a smartphone
* English or Spanish speaking.

Exclusion Criteria:

* pregnant
* not available or willing to use CGM or study device/platform
* serious medical conditions or active thought disorders (e.g., terminal cancer, schizophrenia)

In addition to the self-report of the HbA1c within the past 3 months, potential participants will be screened with a point-of-care (POC) HbA1c (A1CNow®+).

• Soohyun Nam, PhD, APRN, ANP-BC, FAHA, FAAN, Principal investigator, Yale University School of Nursing

NIH grants: R01DK149276