Trial results for a study investigating an extended bolus for meals in a closed-loop system in Type 1 Diabetes were posted on ClinicalTrials.gov on 2026-05-12, with 30 participants enrolled.
Background
Type 1 Diabetes requires careful management of blood glucose levels, particularly around meals. High-fat, high-protein (HFHP) meals present a unique challenge due to their delayed and prolonged impact on glucose absorption, often leading to post-meal hyperglycemia that is difficult to manage with standard insulin bolusing. Closed-loop insulin delivery systems, which automate insulin delivery based on continuous glucose monitoring, aim to improve glycemic control. This study sought to evaluate whether an extended insulin bolus, designed to deliver insulin over a longer period, could improve glucose control specifically for HFHP meals within a closed-loop system, potentially mitigating prolonged hyperglycemia or early hypoglycemia risks.
Trial design
This completed study, designated as Phase NA, enrolled 30 participants with Type 1 Diabetes. The trial compared the use of an extended insulin bolus against a standard insulin bolus for high-fat, high-protein (HFHP) meals within a closed-loop system. The study aimed to assess the impact of the extended bolus on glucose control, specifically looking at metrics such as glucose area under the curve and time spent in various glucose ranges.
Key results
The trial reported several key measurements comparing the standard insulin bolus to the extended insulin bolus for HFHP meals:
- Glucose Area Under Curve [AUC]:
- For the high-fat high protein (HFHP) meal with standard insulin bolus group, the mean AUC was 45371.8 (Standard Deviation 6737.0) (mg/dL*min).
- For the high-fat high protein (HFHP) meal with extended insulin bolus group, the mean AUC was 48641.5 (Standard Deviation 11789.8) (mg/dL*min).
- Percentage of Time Between 70-180 mg/dL:
- The high-fat high protein (HFHP) meal with standard insulin bolus group had a mean of 73.6 (Standard Deviation 22.5) percent of time.
- The high-fat high protein (HFHP) meal with extended insulin bolus group had a mean of 71.3 (Standard Deviation 33.2) percent of time.
- Percentage of Time in Hypoglycemic Range (Defined as < 70 mg/dL):
- Both the high-fat high protein (HFHP) meal with standard insulin bolus group and the high-fat high protein (HFHP) meal with extended insulin bolus group reported a mean of 0.0 (Standard Deviation 0.0) percent of time.
- Average Glucose:
- The high-fat high protein (HFHP) meal with standard insulin bolus group had a mean average glucose of 151.1 (Standard Deviation 22.4) mg/dL.
- The high-fat high protein (HFHP) meal with extended insulin bolus group had a mean average glucose of 161.7 (Standard Deviation 38.9) mg/dL.
- Percentage of Time in Hyperglycemic Range (Defined as ≥180 mg/dL):
- The high-fat high protein (HFHP) meal with standard insulin bolus group had a mean of 26.0 (Standard Deviation 22.5) percent of time.
- The high-fat high protein (HFHP) meal with extended insulin bolus group had a mean of 28.7 (Standard Deviation 33.2) percent of time.
- Insulin Dosage:
- The high-fat high protein (HFHP) meal with standard insulin bolus group received a mean insulin dosage of 15.9 (Standard Deviation 3.0) Units.
- The high-fat high protein (HFHP) meal with extended insulin bolus group received a mean insulin dosage of 15.4 (Standard Deviation 3.7) Units.
What this means
The results suggest that, in this study of 30 participants with Type 1 Diabetes, an extended insulin bolus did not demonstrate an improvement in glucose control for high-fat, high-protein meals when used within a closed-loop system. Key metrics such as Glucose Area Under Curve, average glucose, and percentage of time in the hyperglycemic range were numerically higher with the extended bolus compared to the standard bolus, while the percentage of time within the target glucose range (70-180 mg/dL) was slightly lower. Both groups showed similar rates of time in the hypoglycemic range. The extended bolus also resulted in a slightly lower mean insulin dosage. These findings indicate that for this specific meal type and system, the extended bolus strategy, as implemented, did not achieve the intended improvement in post-meal glucose management.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for the study NCT05454891, titled "Extended Bolus for Meals in a Closed-loop System", were posted on 2026-05-12 on clinicaltrials.gov.