Background and aims: Advanced hybrid closed loop systems (AHCL) are associated with improvement of HbA1c and time in range (TIR). However, AHCL allows to gain even tighter glycaemic control. The aim of this study was to assess the long-term glycaemic outcomes in terms of standard and additional metrics, mainly the time spent in tight range (TiTR, 70-140 mg/dl) and the Glycemia Risk Index (GRI). Methods: In this observational retrospective single center study, adults with T1DM using AHCL with model predictive control (MPC) algorithm (Tandem Control IQ) were enrolled. Data about TiTR, GRI and other standardized metrics have been collected before starting AHCL and 15 days, 3, 6, 9 and 12 months after its initiation. Results: We enrolled 56 subjects with T1DM, aged 44.63 (14.54) years, 34 females (60.7%), duration of disease 18.64 (12.11) years. HbA1c before AHCL was 7.97% (1.10) and 12 months after ACHL was 6.95% (0.77) (p<0.001). TiTR significantly increased in the overall populations (TiTR before AHCL 38.11% (17.05) vs TiTR 12 months 43.10% (13.20) (p=0.059). GRI also improved over 12 months in the overall population from 41.03 (25.47) to 28.55 (16.27) after 12 months (p=0.008) according with the clinical evaluation of the glycaemic control. Accordingly, the other standardized metrics improved over 12 months. An initial increase of insulin daily dose was observed to day 15 from 36.58 IU (18.57) at baseline to 43.51 IU (23.62) at T=+15d (p<0.0001), stable until the end of the observation with 45.08 (26.09) registered at T=12m (p=0.006). Conclusions: AHCL is associated with significant improvement in tighter glycaemic control. AHCL is an effective and safe system to aim to strict metabolic control in all subjects with T1DM, with an increase in TiTR and an improvement in GRI. GRI was evaluated as a performing index for the evaluation of glycaemic control. Based on our knowledge, this is the first real-life study showing an improvement of both these variables, along with the other CGM metrics, in adult T1DM patients using a MPC AHCL system for up to 1 year.