976-P: Evaluation of Hybrid Closed-Loop Insulin Delivery System for Patients with Type 1 Diabetes in Real-World Clinical Practice: A One-Year Qualitative Observational Study

The MiniMed™ 670G (670G) is the first FDA approved hybrid closed-loop insulin delivery system for patients with type 1 diabetes (T1D). In Auto Mode, the integrated continuous glucose monitor (CGM) captures glucose values every five minutes and, via a built-in algorithm, the 670G system automatically adjusts basal insulin delivery targeting a glucose value of 120 mg/dL. Impact of the use of 670G system on patient reported outcomes in people with T1D are limited. Data over one year of use in real world-clinical practice were collected. We evaluated 53 patients with T1D (mean age 46.8±11.8 years, 62% females, body weight 82.5±17.6 kg, BMI 28.7±5.5, HbA1c 7.6±0.8%) who started 670G at the Joslin Clinic between December 2017 and December 2019. Data were collected at baseline and after 12 months. We assessed SROs by administering surveys: 36 Item Short-Form Health Survey (SF 36), Pittsburgh Sleep Quality Index (PSQI), and hypoglycemia fear survey/worry scale (HFS_W). We also measured HbA1c, % time-in-range at baseline and 12 months, and % time in auto mode (TiAM) for the two weeks preceding the final study visit. At 12 months, A1C decreased by 0.3±0.1% from baseline (p<0.01) and % time-in-range increased by 7.9±3.1% from baseline (p=0.015) with no correlation between either of them and %TiAM (p=0.3, p=0.2 respectively). Physical functioning increased by 47.5% from baseline (p<0.001), and HFS_W improved significantly by -16.0% from baseline (p=0.017). At 12 months, average %TiAM was 60.4±33.7% and was not associated with clinical outcomes or SROs. We conclude that use of 670G for a year in real-world clinical practice was associated with significant improvement in A1C, % time-in-range, physical functioning and hypoglycemia fear. Neither of these improvements at 12 months was related to %TiAM.