Development of Diabetes in Adults With Cystic Fibrosis (CF)

Study Overview
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Brief Summary
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This is a crossover study to determine the possible factors that might be related to the development of diabetes in CF and examines the relationship between pancreatic fatigue if any, and the development of diabetes. In addition hormones affecting the release of insulin and stomach motility will be studied to determine if there is a variation in response to solid and liquid meals and if this variation increases as fatigue progresses.

Detailed Description
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The main purpose of this study is to look at possible additional factors that might be related to the development of Cystic Fibrosis Related Diabetes (CFRD), that in itself is a unique entity and to identify an appropriate test to diagnose CFRD. There is well demonstrated evidence of delayed insulin release and peak in individuals with CF, the cause of which is not fully explained. With a view to determine the cause of this phenomenon the aims of this study are: To determine whether pancreatic fatigue contributes to this delayed insulin release and peak that is seen in patients with cystic fibrosis. Should a glucose tolerance test be done at a later time in the day, as against first thing in the morning as is the current accepted standard? To determine if gastric emptying has a role to play in the development of CFRD? To study the hormone release response to a glucose challenge and the patterns of change through the day. To study the relationship of these hormones to gastric emptying and the development of diabetes.

Official Title
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Factors Responsible for the Development of Diabetes in Adults With Cystic Fibrosis

Conditions
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Cystic Fibrosis

Intervention / Treatment
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* Other: Oral Glucose Tolerance Test (OGTT) assessment arm
* Other: Mixed meal test evaluation test arm


Participation Criteria
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Eligibility Criteria
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In order to participate in the study, the CF group must meet all the following inclusion criteria Male or female with a confirmed diagnosis of cystic fibrosis defined by Clinical features consistent with a diagnosis of CF AND Sweat chloride ≥60mmol/L by pilocarpine ionotophoresis; OR Genotypic confirmation of CFTR mutation Aged 18 - 50 years Out-patients from the regional adult unit in Liverpool Currently not known to be diabetic or on insulin Clinically stable over the preceding 4 weeks i.e. no indication for iv antibiotics, steroids or hospital admissions Hemoglobin value >10g/dl The inclusion criteria for the normal population group is as follows: Male or female with NO confirmed diagnosis of cystic fibrosis Aged 18 - 50 years Currently not known to be diabetic or on insulin Clinically stable over the preceding 4 weeks i.e. no indication for iv antibiotics, steroids or hospital admissions Hemoglobin value >10g/dl In order to participate subjects must not meet any of the following exclusion criteria Patients with known diabetes or on glucose lowering medications (insulin, oral agents) On-going acute illness Those on long-term oral steroids Pregnant women Those on immunosuppressive treatment History of, or planned organ transplant Clinically significant abnormal findings on haematology or clinical chemistry Subjects with documented or suspected, clinically significant, alcohol or drug abuse. The determination of clinical significance will be determined by the investigator. Current malignant disease Any serious or active medical or psychiatric illness, which in eth opinion of the investigator, would interfere with subject treatment, assessment, or compliance with the protocol.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Non-Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: OGTT test<br>Comparison of responses to a OGTT between CF subjects and health control subjects | Other: Oral Glucose Tolerance Test (OGTT) assessment arm<br>* Hormonal and motility responses to a standard OGTT evaluation arm<br>|
| Other: Mixed meal<br>Comparison of responses to a mixed meal through the day between CF subjects and health control subjects | Other: Mixed meal test evaluation test arm<br>* Evaluate the hormonal and motility responses to a standard mixed meal test through the day<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Glucose levels | Glucose sensitivity test | 4 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Insulin responses | Insulin resistance test | 4 hours | 
| GLP1 and GIP responses | GLP1 and GIP tests | 4 hours | 
| Evaluation of gastric emptying | Gastric flow measurement | 8 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Gastric emptying, Cystic Fibrosis related diabetes, Incretins