Simplified Meal Approach Using Hybrid Closed-loop Insulin Delivery in Youth and Young Adults With Type 1 Diabetes

The purpose of the study is to examine whether a simplified meal approach (as compared to exact carbohydrate counting) can alleviate the need of carbohydrate counting without worsening postprandial control in youth and young adults with type 1 diabetes using hybrid closed-loop insulin delivery with the Cambridge Artificial Pancreas FX System (CamAPS FX system).

Optimal glycaemic control is the aim of diabetes care and critical in the prevention of diabetes-related complications. Despite advances in diabetes technologies and medications, many current youth and young adults (YYA) with type 1 diabetes (T1D) are not meeting desired glycaemic targets, representing a missed opportunity for improving lifetime outcomes.

A variety of factors including peer group influences, importance of body image, less parental oversight, greater risk-taking, and performance pressure challenge daily self-management in YYA with T1D. Disengagement from care and barriers for optimal glycaemic management in YYA have been mainly shown to be substantially influenced by perceived burden of daily tasks.

Although the recently introduced closed-loop systems, which link insulin delivery to sensor glucose levels, offer promising opportunities to improve glucose control in YYA with T1D, they still require the user to estimate carbohydrates. The perceived burden of exact carbohydrate counting (ECC), the limited evidence supporting its glycaemic benefit and corrective potential of algorithm-driven background insulin titration question its necessity during hybrid-closed loop insulin treatment. Instead, a simplified meal approach (SMA), which only requires the user to select the meal carbohydrate category (small/medium/large), has the potential to alleviate the burden of ECC during hybrid closed-loop insulin therapy whilst resulting in similar glycaemic benefits.

The investigators therefore hypothesize that a simplified meal approach (SMA) using the CamAPS FX system would achieve comparable glucose control compared with the use of the CamAPS FX system with ECC in YYA with T1D.

Eligibility Criteria:
Inclusion Criteria:

* Written informed consent
* Type 1 diabetes as defined by the World Health Organization for at least 6 months
* Age between 12 and 20 years (inclusive)
* Proficient use of continuous glucose monitoring (CGM) or flash glucose monitoring (FGM) for at least 5 days in the past
* Glycated hemoglobin A1c (HbA1c) ≤12%
* The participant is willing to wear closed-loop devices
* The participant is willing to follow study specific instructions
* Negative urine-pregnancy test in sexually active female participants of childbearing potential at screening-visit

Exclusion Criteria:

* Any physical or psychological disease or condition likely to interfere with the normal conduct of the study and interpretation of the study results
* Known or suspected allergy against insulin
* Participant is pregnant or breast feeding or planning pregnancy within next 6.5 months
* Severe visual impairment
* Severe hearing impairment
* Lack of reliable telephone facility for contact
* Concomitant participation in another trial that interferes with the normal conduct of the study and interpretation of the study results
* Participant not proficient in German