The goal of this clinical trial is to learn about the variability of HGI (Hemoglobin Glycation Index) over time in patients living with diabetes using a continuous glucose monitoring.

Inclusion Criteria:

• Major (adult subject over 18), with no upper age limit
• Enrolled in a social security scheme or beneficiary of such a scheme
• Agreement to participate (informed, written consent)
• Established diabetes (regardless the type of diabetes), known for at least 6 months at inclusion
• Regular user of a glucose monitoring system for at least 3 months.

Non inclusion Criteria:

• Known hemoglobinopathy
• Inadequate use of the flash glucose monitoring system with a capture rate of less than 70% of interstitial glucose measurements, during the 3 months preceding the inclusion visit.
• Stage 5 renal insufficiency (CKD-EPI less than 15 mL/min/1.73 m2)
• Pregnant or breast-feeding
• Major under guardianship, curatorship or safeguard of justice
• Any situation assessed by the investigator as potentially prejudicial to the participant's health as a result of participation in the study

Exclusion criteria:

• Treatment with corticosteroids in the 3 months preceding the visit
• Unusual acute situation (infection, very unusual physical activity, etc.) deemed significant by the investigator
• Pregnancy started