The purpose of this study is to determine the effect of hybrid closed loop on glycemic outcomes in young patients aged between 15 and 25 years old with type 1 diabetes, whatever is their initial metabolic control.

Type 1 diabetes (T1D) constitutes a major public health challenge due to acute complications requiring emergency hospitalizations, as well as many chronic complications that need to be managed over the long term. However, these complications can be prevented by maintaining correct glycemic control, according to international guidelines.

For the past few years, the arrival of new technologies as insulin pump and particularly Continuous Glucose Monitoring (CGM) showed a significant improvement on metabolic control.

Nevertheless, adolescents and young adults with type 1 diabetes need a special focus because they still fail to meet glycemic control targets.

At this time, hybrid closed loop, pairing Continuous Glucose Monitoring with insulin pump, enables insulin delivery in a semi-autonomous way thanks to algorithms, and leads to the best metabolic results we've never got in randomized trials and real-world studies.

Inclusion Criteria:

• Patient aged between 15 and 25 years old
• Type 1 diabetes since at least 1 year at the moment of instauring HCL
• At least 3 months of HCL use

Exclusion Criteria:

• Informed patient that have been opposed for their data collect

Tertiary care center from Centre Hospitalier Sud Francilien