Changes in Person-reported Outcomes and Behavior Using the Accu-Chek SmartGuide CGM and Predict App

Changes in Person-reported Outcomes and Behavior Due to a Predictive Algorithm: A Pre-post Trial With the Accu-Chek SmartGuide CGM and the Predict App Solution

The goal of this controlled pre-post-trial is to test the Accu-Chek SmartGuide continuous glucose monitoring (CGM) system and whether its predictive features provide additional benefits for adults with type 1 diabetes or insulin- treated type 2 diabetes.

The main questions this study aims to answer are:

• Does using the Accu-Chek SmartGuide together with the Predict App change participants' fear of hypoglycemia?
• Does the Predict App affect other psychological and behavioral outcomes, such as sleep quality, confidence in preventing hypoglycemia, diabetes- related distress, and diabetes empowerment?
• Does the use of the predictive features affect glucose levels and the way participants use and respond to CGM alarms and trend information?

Participants will use the Accu-Chek SmartGuide for 6 weeks. During the first 2 weeks, participants will use the CGM system without the predictive features. During the following 4 weeks, participants will use the system together with the Accu-Chek SmartGuide Predict App. Participants will complete online questionnaires at two time points (after 2 and after 6 weeks) and answer short questions twice a day through a smartphone app during the first 2 weeks and the last 2 weeks of the study. CGM data will be collected throughout the study. A subgroup of 10 participants will also be invited to take part in an online interview about their experiences with the predictive features.

Continuous glucose monitoring (CGM) is widely used by people with insulin- treated diabetes to monitor glucose levels and support daily diabetes management. The Accu-Chek SmartGuide CGM system provides continuous glucose measurements and includes predictive features that are intended to provide information about possible future glucose trends.

This study will investigate the use of the Accu-Chek SmartGuide with and without these predictive features in adults with type 1 diabetes or type 2 diabetes treated with intensified insulin therapy. The study will be conducted remotely in Germany through the dia*link online panel. No in-person study visits are planned.

Participants will use the Accu-Chek SmartGuide CGM system for a total of 6 weeks. The study consists of two consecutive phases. During the first 2 weeks, participants will use the Accu-Chek SmartGuide CGM without the Predict App and therefore without the predictive features. This phase provides a period in which CGM data and self-reported outcomes can be assessed before the predictive features are introduced. After 2 weeks, participants will receive training on the Predict App and begin a 4-week period using the Accu-Chek SmartGuide together with the Predict App.

Participants will complete online questionnaires at the end of the first 2 weeks and at the end of the 6-week study period. The questionnaires assess fear of hypoglycemia, sleep quality, confidence in preventing hypoglycemia, diabetes- related distress, and diabetes empowerment.

During the first 2 weeks and the last 2 weeks of the study, participants will also complete short ecological momentary assessment (EMA) questionnaires twice daily using a smartphone app. The morning assessment asks about sleep quality and confidence in preventing hypoglycemia. The evening assessment asks about the use and evaluation of CGM functions, including trend arrows, alarms, and predictive features. Participants will also be asked about possible therapy adjustments, satisfaction with the CGM functions, and diabetes- related distress, including distress related to hypoglycemia, hyperglycemia, and glucose variability.

CGM data will be collected throughout both study phases. These data will include measures such as time in glucose ranges, hypoglycemia, hyperglycemia, glucose variability, and mean glucose levels. The study will assess changes in these measures between the two study phases.

The primary outcome is the change in fear of hypoglycemia during the 4-week period in which participants use the Accu-Chek SmartGuide together with the Predict App. Secondary outcomes include changes in other psychosocial outcomes, diabetes-related behaviors, use and evaluation of CGM alarms and trend arrows, and CGM-derived glucose measures.

In addition, a subgroup of 10 participants will be invited to take part in a semi-structured online interview after completing the study. The interviews will explore participants' experiences with the predictive features, their confidence and trust in these features, perceived benefits in everyday diabetes management, and suggestions for improvement. Participants will be selected to achieve a balanced representation with regard to age, sex, and type of diabetes.

Inclusion Criteria:

• Type 1 diabetes or Type 2 diabetes with intensified insulin therapy (defined as basal-bolus therapy with self-adjustment of bolus doses)
• CGM use during the past 3 months (without predictive features)
• Age ≥ 18 years
• HbA1c < 10%
• Informed consent

Exclusion Criteria:

• Use of the SmartGuide CGM solution
• AID use
• Current treatment with psychiatric medications
• Diabetes duration < 3 months
• Current or planned pregnancy
• Peripheral neuropathy that will impact sleep quality according to the judgement of the participant
• Severe complications (e.g. kidney disease, cancer)