Cystic Fibrosis-related DiabetesPhase 4NCT04533646
Comparison of Meal-Time Dosing of Insulin in Cystic Fibrosis Related Diabetes
A Phase 4 study testing Insulin and Continuous glucose monitor (CGM) in people with Cystic Fibrosis-related Diabetes, run by Jagdeesh Ullal at 1 site in United States.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 to 80 years
- Conditions the study is for
- Cystic Fibrosis-related Diabetes
- What is being tested?
- Insulin and Continuous glucose monitor (CGM)
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 13 participants
- Where
- 1 siteUnited States
- Study dates
- 15 Sep 2020to 1 Sep 2025
- Phase
- Phase 4
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age >18 age of years
- Diagnosis of cystic fibrosis related diabetes
- Using basal bolus insulin
- Cystic Fibrosis with Lung Transplantation
Who cannot join
- Use of continuous glucose monitors
- Patient unable to check fingerstick blood sugars
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Pittsburgh Medical Center, Center for Diabetes and Endocrinology
Pittsburgh, Pennsylvania, 15213
About this study
Official title: 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.
Read the 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:
- 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
- Participants who utilize carbohydrate counting will have fewer hypoglycemia events compared to participants who use fixed-dose meal-time insulin
Specific Aims:
- 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.
- 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.
- To test the use of 'rule of 500' for carb counting estimation in patients with CFRD
- To compare the effect of two methods of rapid-acting insulin delivery on fasting glycemia
- Conditions
- Cystic Fibrosis-related Diabetes
- Being tested
- Insulin, Continuous glucose monitor (CGM)
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
InsulinDrug
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.
Continuous glucose monitor (CGM)Device
Participants will be required to wear a CGM to measure glucose trends
| Study group | Role | What they receive |
|---|---|---|
| Fixed Dosing, Followed by Carbohydrate Counting | Experimental | Dosing of premeal insulin with fixed doses Receives: Drug: Insulin; Device: Continuous glucose monitor (CGM) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Time in Target
Measurement of percentage of time in target of glucose level
Measured: 2 weeks
Secondary outcomes (1)
Hypoglycemia
To determine the time spent in hypoglycemia as defined as blood sugar under 70 mg/dl
Measured: 2 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted31 Aug 2020
- Study start15 Sep 2020
- Primary completion31 Jul 2023
- Study completion1 Sep 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Cystic Fibrosis-related DiabetesStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- This study design involves a within-subjects comparison using a sequential cross over that occurs over a 2-week time frame. During the first seven days of wear, the participants will be asked to dose their mealtime rapid-acting insulin by fixed-dose, and the next seven days, participants will be asked to dose their mealtime rapid-acting insulin by carbohydrate counting. After the 14 days, participants will return their continuous glucose monitor (CGM) devices for analysis and interpretation.
- Masking
- None (open label)
- Enrolment
- 13 participants (actual)
Sponsor and investigators
- Lead sponsor
- Jagdeesh Ullal
- Sponsor type
- University, hospital or other
- Collaborators
- Wake Forest University Health Sciences
- Responsible party
- Sponsor-investigator, Jagdeesh Ullal, University of Pittsburgh
- Investigators
- Jagdeesh Ullal, MD, Principal investigator, University of Pittsburgh Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04533646
- Sponsor's protocol ID
- STUDY20060197
- Status last verified
- Oct 2025
- First submitted
- 23 Aug 2020
- Last updated
- 15 Oct 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 15 Oct 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- 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
- ClinicalTrials.gov ID
- NCT04533646
- Acronym / sponsor ID
- STUDY20060197
- Conditions
- Cystic Fibrosis-related Diabetes
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 13 participants (actual)
- Lead sponsor
- Jagdeesh UllalUniversity, hospital or other
- Collaborators
- Wake Forest University Health Sciences
- Study start
- 15 Sep 2020 (actual)
- Primary completion
- 31 Jul 2023 (actual)
- Study completion
- 1 Sep 2025 (actual)
- First posted
- 31 Aug 2020 (actual)
- Results
- Posted 19 Mar 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
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:
- 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
- Participants who utilize carbohydrate counting will have fewer hypoglycemia events compared to participants who use fixed-dose meal-time insulin
Specific Aims:
- 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.
- 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.
- To test the use of 'rule of 500' for carb counting estimation in patients with CFRD
- To compare the effect of two methods of rapid-acting insulin delivery on fasting glycemia
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- This study design involves a within-subjects comparison using a sequential cross over that occurs over a 2-week time frame. During the first seven days of wear, the participants will be asked to dose their mealtime rapid-acting insulin by fixed-dose, and the next seven days, participants will be asked to dose their mealtime rapid-acting insulin by carbohydrate counting. After the 14 days, participants will return their continuous glucose monitor (CGM) devices for analysis and interpretation.
| Arm | Type | Receives |
|---|---|---|
| Fixed Dosing, Followed by Carbohydrate Counting | Experimental | Drug: Insulin, Device: Continuous glucose monitor (CGM)Dosing of premeal insulin with fixed doses |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Age >18 age of years
- Diagnosis of cystic fibrosis related diabetes
- Using basal bolus insulin
- Cystic Fibrosis with Lung Transplantation
Key exclusion criteria (2 listed)
- Use of continuous glucose monitors
- Patient unable to check fingerstick blood sugars
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| InsulinParticipants 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. | Drug | Fixed Dosing, Followed by Carbohydrate Counting |
| Continuous glucose monitor (CGM)Participants will be required to wear a CGM to measure glucose trends | Device | Fixed Dosing, Followed by Carbohydrate Counting |
Primary outcome
Time in Target
Time frame: 2 weeks
Measurement of percentage of time in target of glucose level
1 secondary outcome
Hypoglycemia
Time frame: 2 weeks
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 Oct 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Individual participant dataSharing planned: No
Related trials for Cystic Fibrosis-related Diabetes
Recruiting
ACCESS 2: AI for pediatriC diabetiC Eye examS Study 2
Type 1 Diabetes, Type 2 Diabetes
Active, not recruitingPhase 2/3
SGLT2 Inhibitor Therapy in Cystic Fibrosis-related Diabetes
Cystic Fibrosis-related Diabetes, Cystic Fibrosis
Active, not recruitingPhase 3
Bionic Pancreas in CFRD
Cystic Fibrosis-related Diabetes
RecruitingPhase 1
Dorzagliatin in Pancreatic Insufficient Cystic Fibrosis
Pancreatic Insufficiency, Cystic Fibrosis-related Diabetes
Enrolling by invitationObservational study
Glucose Metabolism in Cystic Fibrosis Related Diabetes (CFRD)
Cystic Fibrosis Related Diabetes
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Jagdeesh Ullal, MD principal investigator
University of Pittsburgh Medical Center
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Insulin and Continuous glucose monitor (CGM) in people with Cystic Fibrosis-related Diabetes, run by Jagdeesh Ullal at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 15 Oct 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 19 Mar 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Time in Target (time frame: 2 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 Oct 2025; AzTrials last refreshed its copy on 8 Nov 2026.