Comparison of Meal-Time Dosing of Insulin in Cystic Fibrosis Related Diabetes

October 17, 2023 updated by: Jagdeesh Ullal

Comparison of Meal-Time Dosing of Rapid Acting Insulin Using Carbohydrate Counting vs. Fixed Doses Utilizing Continuous Glucose Monitoring In Patients With Cystic Fibrosis Related Diabetes

The aim of this study is to assess the utility of CGMs to determine the optimal method to dose meal-time insulin. The investigators will examine glucose excursions in patients with CF who will dose meal-time rapid-acting insulin by carbohydrate counting versus fixed-dose rapid-acting insulin. The carbohydrate ratio and fixed doses will be determined by existing doses, total daily insulin doses, body weight, and insulin sensitivity along with predisposition to hypoglycemia. Bolus insulin dosing is an important part of CFRD management due to the high nutritional demands of these patients. If dosed incorrectly, this could lead to marked hyperglycemia and could worsen nutritional status due to urinary glucose losses. In this project, the investigators will perform a within-subjects' comparison of the 2 standard methods of meal-time rapid-acting insulin dosing.

Study Overview

Status

Active, not recruiting

Detailed Description

Background and Introduction Cystic fibrosis-related diabetes (CFRD) is the most common extra-pulmonary comorbidity in patients with cystic fibrosis (CF). CFRD is also associated with an accelerated decline in pulmonary function, increased pulmonary exacerbations, and increased mortality. Continuous glucose monitoring (CGM) involves the use of a small disposable sensor sited in the subcutaneous interstitial fluid that makes frequent glucose measurements. There is data suggesting that the Medtronic iPro continuous glucose monitors (CGM) can predict hemoglobin a1c levels in patients with CFRD.

The aim of this study is to assess the utility of CGMs to determine the optimal method to dose meal-time insulin. The investigators will examine glucose excursions in patients with CF who will dose meal-time rapid-acting insulin by carbohydrate counting versus fixed-dose rapid-acting insulin. The carbohydrate ratio and fixed doses will be determined by existing doses, total daily insulin doses, body weight, and insulin sensitivity along with predisposition to hypoglycemia. Bolus insulin dosing is an important part of CFRD management due to the high nutritional demands of these patients. If dosed incorrectly, this could lead to marked hyperglycemia and could worsen nutritional status due to urinary glucose losses. In this project, the investigators will perform a within-subjects' comparison of the 2 standard methods of meal-time rapid-acting insulin dosing.

Hypothesis:

  1. Postprandial interstitial fluid glucose levels in participants who utilize carbohydrate counting to dose mealtime rapid-acting insulin will have improved control as defined as the area under the curve and time in target compared to participants who used fixed-dose mealtime insulin
  2. Participants who utilize carbohydrate counting will have fewer hypoglycemia events compared to participants who use fixed-dose meal-time insulin

Specific Aims:

  1. To compare within-subject glucose excursions defined as the percentage of time in target glucose level, percentage of glucose in target, and peak postprandial glucose with fixed insulin dosing versus carbohydrate count based insulin dosing.
  2. To compare the frequency and duration of hypoglycemia (defined as the daily, weekly, and average duration of the event) between insulin delivery methods described above.
  3. To test the use of 'rule of 500' for carb counting estimation in patients with CFRD
  4. To compare the effect of two methods of rapid-acting insulin delivery on fasting glycemia

Study Type

Interventional

Enrollment (Estimated)

20

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

  • Name: Jagdeesh Ullal, MD
  • Phone Number: 412-864-2780
  • Email: ullalj@upmc.edu

Study Contact Backup

Study Locations

    • Pennsylvania
      • Pittsburgh, Pennsylvania, United States, 15213
        • University of Pittsburgh Medical Center, Center for Diabetes and Endocrinology

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 80 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age >18 age of years
  • Diagnosis of cystic fibrosis related diabetes
  • Using basal bolus insulin
  • Cystic Fibrosis with Lung Transplantation

Exclusion Criteria:

  • Use of continuous glucose monitors
  • Patient unable to check fingerstick blood sugars

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Fixed Dosing, Followed by Carbohydrate Counting
Dosing of premeal insulin with fixed doses
Participants will be asked to dose insulin during the first week using fixed doses. During the second week of the study, participants will dose insulin based on carbohydrate counting. Blood sugar control will be compared between the 2 weeks to determine the outcomes of the study.
Participants will be required to wear a CGM to measure glucose trends

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Time in Target
Time Frame: 2 weeks
Measurement of percentage of time in target of glucose level
2 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Hypoglycemia number
Time Frame: 2 weeks
To determine the number of hypoglycemic events under 70 mg/dl
2 weeks
Hypoglycemia duration
Time Frame: 2 weeks
To determine the duration of hypoglycemic events in minutes
2 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Investigators

  • Principal Investigator: Jagdeesh Ullal, MD, University of Pittsburgh Medical Center

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 17, 2021

Primary Completion (Estimated)

September 1, 2024

Study Completion (Estimated)

December 1, 2024

Study Registration Dates

First Submitted

August 23, 2020

First Submitted That Met QC Criteria

August 26, 2020

First Posted (Actual)

August 31, 2020

Study Record Updates

Last Update Posted (Actual)

October 19, 2023

Last Update Submitted That Met QC Criteria

October 17, 2023

Last Verified

October 1, 2023

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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