Adjustment of Open-Loop Settings to Improve Closed-Loop Results in Type 1 Diabetes: A Multicenter Randomized Trial

Area of Science:

• Endocrinology
• Biomedical Engineering
• Diabetes Technology

Background:

• Closed-loop control (CLC) systems for diabetes management rely on pre-set open-loop insulin pump parameters.
• Optimizing these initial settings is time-consuming and labor-intensive.

Purpose of the Study:

• To evaluate the impact of a one-time algorithmic adjustment of basal rate and insulin-to-carbohydrate ratio on CLC performance.
• To assess if automated setting optimization enhances glycemic control within a CLC system.

Main Methods:

• A multicenter, randomized, crossover trial involving 37 adults with type 1 diabetes.
• Participants underwent two 27-hour CLC periods: one with standard settings and one with algorithmically adjusted settings.
• Standardized glucose monitoring and meal/exercise protocols were followed.

Main Results:

• The median time spent within the target glucose range (80-140 mg/dL) was comparable between the control and adjusted groups (39.7% vs. 44.2%).
• Both groups exhibited minimal time spent in hypoglycemia (less than 70 mg/dL), with medians of 1.34% and 1.37%.
• No significant differences in time above 140 mg/dL were observed.

Conclusions:

• A single algorithmic adjustment of open-loop settings did not improve glucose control during short-term outpatient CLC.
• The CLC system demonstrated significant adaptability and safety, maintaining low rates of hypoglycemia regardless of initial setting optimization.