Abnormal glucose tolerance in children with cystic fibrosis: the predictive role of continuous glucose monitoring system

Abstract

A long pre-diabetic phase of abnormal glucose tolerance is described in subjects with cystic fibrosis (CF) since childhood. Objective: The aims of the study were to compare oral glucose tolerance test (OGTT) and continuous glucose monitoring system (CGMS) in the diagnosis of altered glucose metabolism, and to longitudinally evaluate the role of CGMS in predicting glucose metabolism deterioration in children with CF. Methods: Seventeen children with CF and 14 controls were enrolled (mean age 13.3G3.0 years). All subjects underwent OGTT and CGMS registration. On the basis of OGTT, children were classified as normal glucose tolerance, impaired glucose tolerance (IGT), IGT plus at least one glucose value above 200 mg/dl at intermediate OGTT points (IGTC200) and CF-related diabetes (CFRD). HbA1c, glucose area under the curve, insulin sensitivity, and insulinogenic and disposition indexes were also considered. Subjects with CF underwent another OGTT after 2.5 years. Results: Baseline OGTT revealed 3/17 (7.6%) children with CF with at least one glucose value above 200 mg/dl (1 CFRD and 2 IGTC200), while CGMS revealed 6/17 (35.3%) children with glucose excursions above 200 mg/dl (PZ0.010). None of the controls showed glucose over 200 mg/dl either at OGTT or at CGMS. At the 2.5-year follow-up OGTT, all the six subjects who had diabetic glucose excursion (i.e. O200 mg/dl) at baseline CGMS presented IGTC200 or CFRD. In logistic regression analysis, CGMS diabetic excursion was the strongest predictor of IGTC200 and CFRD (P!0.001). Conclusions: CGMS could be a useful tool to predict glucose metabolism derangements in children affected by CF.

Clinical Use of Continuous Glucose Monitoring in Adults with Type 1 Diabetes

“…[8][9][10] CGM for Guiding Diabetes Management CGM systems can be used blinded or open. When we are using CGM short-term to identify trends, such as postprandial glucose peaks, hypoglycemia, and dawn phenomenon, it is often cleaner to use blinded CGM where data are not displayed to the patient and therefore cannot be used to influence the readings.…”

Cystic fibrosis-related diabetes: links, challenges, and future directions

“…80 Glucose excursions .200 mg/dL on CGM successfully predicted the development of IGT or CFRD as diagnosed by OGTT in a 2.5-year period. 81 Hameed 82 confirmed the validity and reproducibility of CGM in over 100 children with CF.…”

Diagnosing cystic fibrosis-related diabetes: current methods and challenges

“…In contrast, a 0 and 120minute OGTT will only give 2 plasma glucose values following an overnight fast and standard glucose load. A CF patient with normal glucose tolerance by OGTT may have frequent intermittent post-prandial hyperglycaemia on CGM [59,100,101]. It has been postulated that glucose levels can be normal during the OGTT, but elevated on CGM, because patients with CF may eat a carbohydrate load at home that exceeds the glucose level consumed in an OGTT.…”