Continuous glucose monitoring system in the screening of early glucose derangements in children and adolescents with cystic fibrosis

Background: In cystic fibrosis (CF), diabetes mellitus (DM) is associated with progression of pulmonary disease and nutritional impairment. Aim: To compare oral glucose tolerance test (OGTT) and continuous glucose monitoring system (CGMS) in patients with CF with early glucose derangements. Patients and Methods: Thirty-two patients with CF (5-20 years) with intermediate glucose values >7.7 mmol/l during OGTT received a CGMS registration. Patients were classified into those with normal glucose tolerance (NGT), impaired glucose tolerance (IGT) and DM, according to glucose values at 120 min of. OGTT and during CGMS. Furthermore BMI z-scores, forced expiratory volume in 1 second (FEV1%), number of respiratory infections/year, enzyme supplementation, and HbA(1c) were evaluated. Results: OGTT and CGMS derangements were in agreement in 43.7% of the patients. BMI z-scores, FEV1%, number of respiratory infections/year, enzyme supplementation, and HbA(1c) did not differ among the three groups. HbA(1c) correlated positively with 120 min OGTT (r = 0.34; p = 0.059), CGMS area (r = 0.35; p = 0.048) and the number of respiratory infections, and negatively with FEV1%. Conclusions: Intermediate glucose values during OGTT should be considered as a screening test in patients with CF. CGMS can be useful in studying the early occurrence of glucose derangements in selected patients.