Supplementary Material for: Use of the Loop Open-Source Automated Insulin Delivery System in Children with Type 1 Diabetes: Six-Month Results from a Single Center

Introduction: As an alternative to commercial automated insulin delivery (AID) systems open-source AID (OS-AID) technologies such as Loop had growing interest among people with type 1 diabetes (T1D). This study aims to evaluate the six-month glycemic outcomes of children using the Loop iOS.3 system. Methods: A total of fifty children aged 2–18 years with a minimum 6-month T1D duration, initiated Loop OS-AID between May 2023 and May 2024. Data from continuous glucose monitoring and insulin delivery were collected and analyzed at baseline, 3 months, and 6 months. Primary outcomes included time in range (TIR, 3.9 – 10mmol/L [70–180 mg/dL]), time above range (TAR), time below range (TBR), glucose management indicator (GMI), and HbA1c. Results: TIR improved significantly from 68.3% at baseline to 72.7% at 6 months (p=0.003). The proportion of participants with TIR >70% increased from 46% to 66% (p=0.012). The mean HbA1c value showed a significant decrease from baseline to month 6 (53 mmol/mol [7.0%] vs. 49 mmol/mol [6.6%], p=0.006), although HbA1c measurements were available for a limited number of participants. TAR1 > 10mmol/L (180 mg/dL) decreased (2 vs 17.1 p 13.8mmol/L (250mg/dl) showed a slight, non-significant reduction (5 vs 4 p=0.363). TBR1 <3.9mmol/L (70mg/dL) and TBR2 <3mmol/L (54mg/dL) remained stable (3 vs 3, p1=0.474; 0.7 vs 0.9, p2=0.560). The basal insulin ratio dropped significantly (40.3% vs 19.7%, p <0.001), suggesting a shift in dosing dynamics due to the algorithm’s automatic correction bolus strategy. Conclusion: Use of the Loop OS-AID system resulted in improved glycemic outcomes without increased risk of hypoglycemia or DKA (Diabetic ketoacidosis). These findings support Loop as a safe and effective alternative for pediatric T1D management. Further large-scale and longer-term studies are warranted.