Diabetes is reaching epidemic proportions and a targeted glucose control is key to prevent microvascular complications as well as long-term macrovascular disease.

Self-monitoring of blood glucose (SMBG) in type 1 diabetes (T1D) is mandatory to implement safe and effective adjustments in insulin therapy in order to reduce glucose levels and prevent hypoglycemic episodes. It is known that a higher rate of glucose testing (up to 8 times/day) is associated with improved glucose control, however, long-term repeated daily glucose tests are painful, inconvenient and difficult to pursue.

Continuous glucose monitoring (CGM) is an alternative to SMBG, but the use of conventional CGM has been limited by the need of repeated calibration using capillary glucose testing, relatively short sensor lifespan and high costs. The recently introduced CGM FreeStyle Libre™ (Abbott Diabetes Care, Witney, UK) flash glucose monitoring (FGM), a new generation of glucose testing device, has the advantage to be user friendly by just scanning the reader over the sensor.

The FGM system does not require calibration, has a long sensor lifetime of 14 days and it's relatively affordable, explaining the widespread use of the device.

The Flash Glucose Monitoring-FGM is a real-time glycemic monitoring system called "hybrid" as it is not equipped with alarms capable of alerting the patient to cut-off value for the hypo- or hyperglycemia, but allows the glycemic trend to be viewed at request.

Patients will be identified and enrolled in the Diabetes Departments of different hospitals/clinics in the Emilia Romagna region, Italy. Patients will be divided in two groups A (naive patients,) and B (patients already using the device at enrollment) and followed for 12 months.

Study design is observational prospective and includes 3-months follow up visits until the 12-month final evaluation.

At each visit, patient clinical data, adherence and side effects will be recorded and data download from the device will be performed.

Inclusion Criteria:

• Diagnosis of Diabetes Mellitus type 1 for at least 12 months
• Multi-injection insulin therapy
• C-peptide <0.2 nmol/L
• At least 1 documented episode in the last 12 months of hospitalization (emergency room or ordinary hospitalization) for severe hypoglycemia; hospitalization (emergency room. or ordinary hospitalization) for diabetic ketoacidosis; documented severe hypoglycemia (i.e. with blood glucose measurement).

Exclusion Criteria:

• Diabetes Mellitus type 2
• Other types of diabetes
• Other diseases (excluding endocrinopathies, hypertension and dyslipidemia) that required chronic intake of drugs that may interfere with the glucose-insulin system.

Patients with diagnosis of Diabetes Mellitus type 1 for at least 12 months and in multi-injection insulin therapy.