Cystic Fibrosis Related Diabetes Screening. (D2M)

Cystic fibrosis-related diabetes is a late cystic fibrosis (CF) associated comorbidity whose prevalence is increasing sharply lifelong. Guidelines for glucose metabolism (GM) monitoring relies on oral glucose tolerance test . However, this test is neither sensitive nor specific. The aim of this study is to compare sensitivity and specificity of different methods for GM monitoring in children and adolescents with CF. Continuous GM system (CGMS) will be used as the reference method. Results will be compared to those of oral glucose tolerance test (OGTT), intravenous glucose tolerance test (IGTT), homeostasis model assessment index of insulin resistance (HOMA-%IR) , homeostasis model assessment index of beta-cell function (HOMA-%B) and HbA1C dosage (glycated haemoglobin A1C). Patients will be classified into three groups according to CGMS: normal glucose tolerance, impaired glucose tolerance and diabetes mellitus.

glucose solution at a dose of 1.75 g/kg (up to a maximum of 75 g) for the OGTT and glucose solution at a dose of 0.5 g/kg (up to a maximum of 35 g) was injected in 2.5-3 min for the IGTT

At the first visit at day 1an OGTT will be performed then the CGMS is implanted. Capillary glycaemia will be taken four times a day to set up the CGMS. A second visit is scheduled at day 4, where the intravenous glucose tolerance test is performed as well as the HbA1C level.

Measurement of the sensitivity and the specificity of IGTT (intravenous glucose tolerance test) for the diagnosis of diabetes mellitus in comparison to a continuous glucose monitoring system

Measurement of the sensitivity and the specificity of HOMA-%IR (homeostasis model assessment index of insulin resistance) for the diagnosis of diabetes mellitus in comparison to a continuous glucose monitoring system.

Inclusion Criteria: Subjects with confirmed diagnosis of Cystic Fibrosis with a sweat chloride > 60 mmol/L. Subjects will be aged between 10 and 18 years with at least one class 1 or 2 Cystic fibrosis transmembrane conductance regulator (CFTR) mutation. Subjects will be pancreatic insufficient. Subjects must have a forced expiratory volume 1 (FEV1)> 40 % of predicted normal for age, sex and height at the screening visit. Stable CF disease as judged by the investigator Exclusion Criteria: Subjects with glucose intolerance abnormalities Subjects with pulmonary exacerbation within 4 weeks before screening History of lung or hepatic transplantation or awaiting transplantation

Mainguy C, Bellon G, Delaup V, Ginoux T, Kassai-Koupai B, Mazur S, Rabilloud M, Remontet L, Reix P. Sensitivity and specificity of different methods for cystic fibrosis-related diabetes screening: is the oral glucose tolerance test still the standard? J Pediatr Endocrinol Metab. 2017 Jan 1;30(1):27-35. doi: 10.1515/jpem-2016-0184.