LAUSR

Introduction: After a long lead-in period, artificial pancreas (AP) technology is well on its way to revolutionizing the treatment of diabetes, but no AP is currently approved. Recently data about the use of a hybrid closed-loop (CL) insulin delivery has been presented. Aim: We compared two devices, Minimed 640G system, (Medtronic, CA, U.S.) in the market in Italy since mid-2015 vs. Minimed 670G system (Medtronic, CA, U.S.), just entered the market on October 24th, 2018, used by the same patients. Methods: We prospectively analyzed data of 19 patients using 640G three months before switching to 670G. Main outcome is the time in range (TIR) compared to TIR while using 640G. Secondary outcomes are predicted A1c, time in hypo, time in hyper (>160 mg/dl), insulin total daily dose (TDD), %bolus and %basal rate, coefficient of variation (CV). Results: The 19 patients (mean age 13±4 years, range 7-20 years, diabetes duration 7±4 years) who switched to 670G, after 2 months observation had a TIR significantly lower when compared while using 640G (62.9±6.6% vs. 76.6±16.3%, p=0.03), with similar predicted A1c (6,8±0.3% vs. 6.8±0.7%, p=0.89). Time in hypo significantly increased (3.4±2.3% vs. 0.5±0.6%, p=0.001), while no difference has been observed about time in hyper (34.7±5.9% vs. 22.9±16.1%, p=0.38) and CV (40.4±8.5% vs. 43.2±6.5%, p=0.25). Interestingly, TDD is slightly, but not significantly, lower when using 670G, with a higher percentage of insulin given as bolus than as basal rate. Conclusions: 670G system seems less effective than 640G system to achieve a higher TIR, at the expenses of a higher time in hypo. A systematic educational pathway, as the one used by 640G users, could help reach these results, as well as some constrains 670G system has (fixed glycemic target at 120 mg/dl, only simple bolus, etc.). It is solacing to know that we already have useful tools for the best possible care of our patients with type 1 diabetes while we wait for the commercial availability of an AP or a more performant hybrid CL system. Disclosure A.E. Scaramuzza: None. I. Rabbone: None. R. Bonfanti: Advisory Panel; Self; Abbott, Lilly Diabetes, Medtronic, Novo Nordisk A/S, Roche Diabetes Care, Sanofi.