Background and Aims
Hybrid closed-loop systems automatically deliver insulin based on sensor data. MiniMed 670G system operates in Auto Mode but exits to Manual Mode for certain reasons. The aim was to evaluate the duration, frequency and main reasons for exit from Auto Mode to Manual Mode.
Patients with type 1 diabetes using hybrid closed-loop system (Medtronic MiniMed 670G) for 3 months were evaluated. 2-week downloads were analysed to assess all the Auto Mode exits during this period of time.
Data from 58 patients were included, age: 28 ± 15 years (7-63), 59% (n=34) females, diabetes duration: 15 ± 9 years, HbA1c: 7.0 ± 0.6%, TIR (70-180 mg/dl): 73 ± 9%.
Sensor use was 86 ± 13%. Time in Auto Mode was 85 ± 17%. Number of exits was 4 ± 2 per week (0.6 ± 0.3 per day). 16.8% of the exits were not explained. Sensor issues caused the majority of explained exits (39%), followed by hyperglycaemia (23%), auto mode disabled by user (16%) and maximum or minimum insulin delivery (13%). Frequency of exit reasons is shown in Figure 1.
MiniMed 670G hybrid closed loop is maintained in Auto Mode during a high percentage of the time. The main reasons for exit to Manual Mode are sensor related, followed by high sensor glucose. A high percentage of exits are not explained. Time in Auto Mode should be maximized to improve the efficacy of the system and to avoid the burden of frequent interaction with the system for people with type 1 diabetes.