Alternate Measures of Glucose During OGTT Testing for CFRD

Cystic Fibrosis Clinical Trial

Official title:

Correlations Between CGM and Serum Glucose During OGTT Testing for CFRD

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT05568134
• Other study ID #: 22-020249
• Status: Recruiting
• Start date: July 17, 2023
• Est. completion date: February 1, 2026

Study information

• Verified date: March 2024
• Source: Children's Hospital of Philadelphia
• Contact: Grey Baker
• Phone: (215)-590-3174
• Email: bakerg3[@]chop.edu
• Is FDA regulated: No
• Study type: Observational

Clinical Trial Summary

Although early detection and treatment of cystic fibrosis-related diabetes (CFRD) can lead to significant clinical improvements and prolong life, rates of screening are poor likely due to the burdensome nature of oral glucose tolerance testing (OGTT). The investigators propose to assess the feasibility and accuracy of two screening tools, continuous glucose monitoring (CGM) and a home OGTT kit (GTT@home). If this pilot study reveals acceptable accuracy of either device, this study will allow for future studies exploring home-based OGTT screening.

Description:

The investigators hypothesize that there will be strong agreement between plasma glucose and glucose as measured by either CGM or GTT@home at three different timepoints during an OGTT: fasting, 1-hour, and 2-hours.

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 30
• Est. completion date: February 1, 2026
• Est. primary completion date: February 1, 2025
• Accepts healthy volunteers: No
• Gender: All
• Age group: 10 Years and older

Eligibility

Inclusion Criteria:

• Diagnosis of cystic fibrosis
• = 10 years of age
• Fluency in written and spoken English as the GTT@Home is currently only available in English

Exclusion Criteria:

• Hospitalization or treatment with IV antibiotics or supraphysiologic glucocorticoids within 4 weeks
• Major medical or psychiatric disorders other than CF
• Use of medications known to impact the accuracy of the Dexcom G7 (hydroxyurea, >2g acetaminophen per day)
• History of severe adhesive reactions that may lead to an inability to tolerate CGM wear

Related Conditions & MeSH terms

• Cystic Fibrosis
• Cystic Fibrosis-related Diabetes
• Fibrosis

Intervention

Diagnostic Test:
• Oral glucose tolerance test
An oral glucose tolerance test will be completed. A fasting glucose will be measured. Participants will drink 1.75 g/kg of dextrose (up to a maximum of 75 grams) within 10 minutes. Glucose values will be measured at 1 hour and 2 hours.

Locations

Country	Name	City	State
United States	Children's Hospital of Philadelphia	Philadelphia	Pennsylvania

Sponsors (2)

Lead Sponsor	Collaborator
Children's Hospital of Philadelphia	Cystic Fibrosis Foundation

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Agreement between plasma glucose, CGM measured glucose using the Dexcom G7, and GTT@home glucose	Differences in fasting glucose will be measured by the difference in mg/dl between plasma glucose, CGM measured glucose, and GTT@home measured glucose.	Fasting glucose before OGTT
Primary	Agreement between plasma glucose, CGM measured glucose using the Dexcom G7, and GTT@home glucose	Differences in the 1 hour glucose during the OGTT will be measured by the difference in mg/dl between plasma glucose, CGM measured glucose, and GTT@home measured glucose.	1 hour mark in OGTT
Primary	Agreement between plasma glucose, CGM measured glucose using the Dexcom G7, and GTT@home glucose	Differences in the 2 hour glucose during the OGTT will be measured by the difference in mg/dl between plasma glucose, CGM measured glucose, and GTT@home measured glucose.	2 hour mark in OGTT
Secondary	Agreement between the categorical diagnosis of normal glucose tolerance (NGT), impaired glucose tolerance (IGT), indeterminate glycemia (INDET), and CFRD as defined by plasma glucose, CGM glucose, and GTT@home glucose.	Categorical diagnosis of glucose tolerance as measured by plasma glucose, CGM measured glucose using the Dexcom G7, and GTT@home glucose.	Up to 2 hours
Secondary	Difference between plasma glucose and CGM measured glucose after the fasting glucose	Absolute differences between the glucose measurements will be measured in mg/dL	Up to 20 minutes after the fasting glucose
Secondary	Difference between plasma glucose and CGM measured glucose after the 1 hour mark during the OGTT.	Absolute differences between the glucose measurements will be measured in mg/dL	Up to 20 minutes after the 1 hour mark in the OGTT
Secondary	Difference between plasma glucose and CGM measured glucose after the 2 hour mark during the OGTT.	Absolute differences between the glucose measurements will be measured in mg/dL	Up to 20 minutes after the 2 hour mark in the OGTT
Secondary	The ability of untrained participants to successfully complete the GTT@home kit without any guidance from the research team	Number of steps successfully completed as measured by the GTT@home instruction manual.	Up to 2 hours
Secondary	Impact of wearing a real-time CGM on participants' awareness of the importance of screening for and diagnosing CFRD.	60 minute semi-structured interviews will be conducted with participants. Transcripts will be analyzed using semantic content analysis	Within 2 weeks after removal of the CGM
Secondary	Perceived benefits and burdens of CGM use	Participants will complete a CGM Benefits and Burdens survey, a 16-item measure used to assess perceptions of CGM technology in people with type 1 diabetes. Surveys may be completed on paper or online, as per the participant's preference. The survey is scored on a 5-point scale (agree/disagree scale).	Within 2 weeks after removal of the CGM