Cystic Fibrosis, Glucose Intolerance
Conditions
Keywords
children, cystic fibrosis, glucose intolerance, continuous glucose measurement
Brief summary
The aim is to describe the association of glucose tolerance measured with three different tools (continuous glucose measurement system - CGMS, oral glucose tolerance testing - OGTT and optional intravenous glucose tolerance testing -IVGTT) with parameters out of lung function and anthropometric parameters in patients with cystic fibrosis.
Detailed description
Patients with cystic fibrosis (CF) with progressing disease are developing a glucose tolerance which resembles the metabolic state of a diabetic patient because of increasing impairment of endocrine pancreatic function. The prevalence of this diabetic metabolic state is increasing with age, reaching around 20% at the age of 20 years. Over the last decade, research has already highlighted the negative influence of cystic fibrosis related diabetes (CFRD) on morbidity and mortality after the diagnosis of this condition. As the deterioration in nutritional status and lung function can already be noticed 2-6 years before the onset of CFRD, the importance of early diagnosis in glucose abnormalities and its treatment therefore is crucial. The currently used method to evaluate altered glucose metabolism in patients with CF is an annual oral glucose tolerance test (OGTT) with the glucose value after 120 min after oral ingestion of glucose-fluid as reference. This method may detect CFRD much later than we see deterioration of lung function and weight loss. This deterioration and the mortality in CF is related to CFRD. An alternative diagnostic tool that has gained increasing attention and that is already routinely used in pediatric patients with diabetes mellitus type I is the continuous glucose monitoring system (CGMS) which was shown to be much more sensitive in detecting glucose abnormalities. To assess pancreatic endocrine dysfunction - the pathophysiologic cause for glucose intolerance - intravenous glucose tolerance testing (IVGTT) is the gold standard. The investigator's aim is to describe the association of glucose tolerance measured with three different tools/assessment procedures (CGMS, OGTT and optional IVGTT) with lung function and anthropometric parameters.
Interventions
OTHERDiagnostics for glucose tolerance with 3 different methods.
1. A 7-day course of subcutaneous continuous glucose monitoring system (CGMS). 2. An oral glucose tolerance test done within the 7 day period of CGMS. 3. Optionally a intravenous glucose tolerance test done within the 7 day period of CGMS.
Sponsors
Insel Gruppe AG, University Hospital Bern
Christoph Saner
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
10 Years to 20 Years
Healthy volunteers
No
Inclusion criteria
* Patients with confirmed cystic fibrosis aged between 10-20 years, under medical treatment at the University Children's Hospital Basel UKBB and at the University Children's Hospital, Inselspital Bern
Exclusion criteria
* Patients being under medical treatment with systemically administered glucocorticoid drugs or intravenously administered antibiotic treatment within 6 weeks before glucose tolerance testing. * Patients with acute pulmonary exacerbation, defined by a pediatric pneumologist
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| HbA1c | Within the 7 day course of CGMS | — |
| Lung clearance index | Within 3 months of the 7 day course of CGMS | — |
| BMI-SDS (standard deviation score). | At day 1 of the CGMS course | — |
| The glucose values given in mmol/l after 30', 60', 90' and 120 minutes during OGTT. | Within the 7 day course of CGMS | Standard oral glucose tolerance test. |
| First phase insulin secretion and second phase insulin secretion out of IVGTT (intravenous glucose tolerance test). | Within the 7 day course of CGMS | Standard intravenous glucose tolerance test. |
| % time spent above 8mmol/l, the area under the curve and the mean glucose value (in mmol/l) | Beginning at day 1, lasting 7 days | These measurements will be gained out of the 7 day CGMS-course (continuous glucose monitoring system). |
| FEV1% (forced expiratory volume at one second) out of the lung function testing | Within 3 months of the 7 day course of CGMS | — |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Comparing the performance between CGMS and OGTT related to clinical parameters. | 7 days | The investigators compare the fit of a linear regression between the % time above 8mmol/l (out of CGMS) and the lung clearance index (LCI) with the fit of a linear regression of the 120min glucose value (out of OGTT) and the LCI. The same analysis will be performed comparing the fit of a regression between the % time above 8mmol/l (out of CGMS) and the FEV1% (out of lung function) with the fit of a linear regression of the 120min glucose value (out of OGTT) and the FEV1%. Finally, the same analysis will be performed comparing the fit of a linear regression using the % time above 8mmol/l (out of CGMS) and the BMI-SDS with the fit of a linear regression of the 120min glucose value (out of OGTT) and the BMI-SDS. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Characterising glucose profiles over 24 hours | 7 days | The investigators will describe computer-based modelling of the glucose curves obtained with the CGMS, aiming to describe inter-/ and intraindividual variability in the profiles. |
Countries
Switzerland
Outcome results
None listed