ABSTRACT
Objective: The MiniMed 670G hybrid closed-loop (HCL) system was the first FDA-approved automated insulin delivery system for patients with type 1 diabetes (T1D). We aimed in this study to evaluate a 10-day initiation protocol in adults with T1D from multiple daily injections (MDI) to MiniMed 670G HCL system in achieving glycemic control. Methods: We recruited individuals with T1D on MDI, aged 18-65 years with HbA1C less than 12.5% (113 mmol/mol) in an open-label, single-arm study for 3 months. The primary outcome was achievable Time in Range (TIR), 3.9-10 mmol/L (70-180 mg/dL), over the first 84 days after initiation of the Auto Mode of the HCL system. The participants went through a planned 10-day protocol of 2 days to assess their readiness for the HCL system, followed by 5 days of system training in groups of 3-5 individuals, then 3 days of Manual Mode use before starting the Auto Mode. We collected the real-time continuous glucose monitoring (CGM) data at baseline and the CGM, pump settings, and system usage data over the first 84 days of Auto Mode use. Statistical analysis was performed using STATISTICA 12 (StatSoft, Tulsa, USA). Results: We enrolled 24 individuals (13 females), aged 28.8±9 years with T1D for 12.1±7.4 years, mean HbA1C of 8.9±1.4% (74±15.3 mmol/mol), TIR of 48.96±17.9%, time below range (TBR) of 5.96±7.6%, and time above range (TAR) of 43.42±16.8%. One female did not complete the study as she became pregnant. During the first 84 days on the Auto mode of the HCL system, the participants had a median sensor usage of 86% of the time and spent a median time of 83% in Auto Mode. TIR increased to 67.22±13.2% (P = 0.0003), TBR decreased to 3.57±2.9% (P = 0.16), and TAR decreased to 29.22±13.2% (P = 0.0024). The mean HbA1C improved to 7.5±0.8% (59±9.3 mmol/mol) by the end of the study (P = 0.0001). No diabetic ketoacidosis or severe hypoglycemia episodes were recorded during the study. Discussion/Conclusion: Previous studies on MiniMed 670G recruited participants with previous insulin pump experience, while our patients were insulin pump naïve. We used the same 10-day onboarding protocol that was tested before to initiate the 670G HCL system in a study of the pediatric age group reaching a TIR of 75.6±6.9% three months after initiation. The adult participants in our study had significant improvement in HbA1C and TIR, although it was less than what was reported in the pediatric population and this could be related to the conduction of the study during the COVID-19 pandemic. The 670G HCL system improved glycemic control without worsening TBR.