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OpenTrials
Completed

NCT Number: NCT05454891

Extended Bolus for Meals in a Closed-loop System

This study aims to evaluate whether the use of an extended bolus will improve glucose control with high-fat high protein meals using a closed-loop system. The new knowledge gained from this study may provide a method to allow for the proper administration of insulin over an extended period to mitigate the risk of prolonged hyperglycemia or early hypoglycemia.

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Key information

Conditions

Type 1 Diabetes Autoimmune Diseases Diabetes Mellitus Diabetes Mellitus, Type 1 Endocrine System Diseases Glucose Metabolism Disorders Immune System Diseases Metabolic Diseases Nutritional and Metabolic Diseases

Age range

13 year–19 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of California San Francisco

San Francisco, California, 94158, United States

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age between 13 and 19 years old, A1C > 6% at screening
  • Diagnosed with type 1 diabetes for at least one year
  • Total daily dose (TDD) of insulin ≥ 0.3 units/kg/day
  • Currently using the Control IQ closed-loop system
  • Willing to abide by meal recommendations and study procedures
  • Willing and able to sign the Informed Consent Form (ICF) and/or has a parent or guardian willing and able to sign the ICF
  • Use an Android or Apple smartphone
  • Willingness not to start any new non-insulin glucose-lowering agent during the course of the trial
  • Participant and parent(s)/guardian(s) willingness to participate in all training sessions as directed by study staff
  • Parent/guardian proficient in reading and writing English
  • Live in the United States, with no plans to move outside the United States during the study period

Exclusion criteria

  • A1C >10%
  • One or more episodes of severe hypoglycemia or DKA requiring ER visit or hospitalization within the past three months
  • Used non-insulin anti-diabetic medication within the last 30 days other than metformin
  • Known history of gastroparesis, seizure disorder, adrenal insufficiency, or ongoing renal or hepatic disease
  • Pregnancy or lactation
  • Untreated or unstable hypothyroidism
  • Currently undergoing cancer treatment or systemic treatment with steroids
  • Untreated or inadequately treated mental illness
  • Current alcohol abuse
  • Current illness that would interfere with participation in the study
  • Delayed gastric emptying or any concurrent conditions that can be associated with delayed gastric emptying or altered digestion; and the use of any medication that affects gastric emptying
  • Celiac Disease

Treatment and study plan

Tandem t:slim X2 insulin pump: Extended bolus of insulin then standard bolus of insulin

Device

For a standardized HFHP breakfast, participants will receive an extended meal bolus of insulin on the first morning and a standard meal bolus of insulin on the second morning of the study.

Tandem t:slim X2 insulin pump: Standard bolus of insulin then extended bolus of insulin

Device

For a standardized HFHP breakfast, participants will receive a standard bolus of insulin on the first morning and an extended bolus of insulin on the second morning of the study.

Primary outcomes

  1. Glucose Area Under Curve [AUC]

    Time frame: 0 to 5 hours post-meal onset

    Area under the curve between glucose trace and starting glucose (mg/dL* min)

Secondary outcomes

  1. Percentage of Time Between 70-180 mg/dL

    Time frame: 0 to 5 hours post-meal onset

    Percentage of time spent between 70-180 mg/dl based on Continuous Glucose Monitor (CGM) values

  2. Percentage of Time in Hypoglycemic Range (Defined as < 70 mg/dL)

    Time frame: 0 to 5 hours post-meal onset

    Percentage of time spent with blood sugar less than 70 mg/dL based on Continuous Glucose Monitor (CGM) values

  3. Average Glucose

    Time frame: 0 to 5 hours post-meal onset

    Average glucose value based on Continuous Glucose Monitor (CGM) values

  4. Percentage of Time in Hyperglycemic Range (Defined as ≥180 mg/dL);

    Time frame: 0 to 5 hours post-meal onset

    Percentage of time spent with blood sugar higher than 180 mg/dL based on Continuous Glucose Monitor (CGM) values

  5. Insulin Dosage

    Time frame: 0 to 5 hours post-meal onset

    Total insulin received during 5 hrs ( manual bolus as well as automated)

  6. Time to Target (110mg/dL)

    Time frame: 0 to 5 hours post-meal onset

    Time spent till blood glucose returns to 110mg/dL

  7. Time to Baseline

    Time frame: 0 to 5 hours post-meal onset

    Time spent till blood glucose returns to baseline

  8. Time to Peak Glucose

    Time frame: 0 to 5 hours post-meal onset

    Time spent till blood glucose reaches the maximum value after meal

  9. Change in Glucose

    Time frame: 0 to 5 hours post-meal onset

    The difference between baseline to max glucose value

  10. Peak Glucose Concentration

    Time frame: 0 to 5 hours post-meal onset

    Max blood glucose

  11. Percentage of Time Between 70-140 mg/dL

    Time frame: 0 to 5 hours post-meal onset

    Percent of glucose readings from CGM system between 70-140 mg/dL per unit of time

Sponsors and collaborators

Lead sponsor

University of California, San Francisco

Other

Collaborators

  • National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Registry information

Official study title

Postprandial Glucose Control Using an Extended Bolus for High-fat High Protein Meals in a Closed-loop System in Patients With Type 1 Diabetes

Important dates

Study start
2022
Primary completion
2024
Study completion
2024
First posted
Jul 12, 2022
Registry last updated
May 12, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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