Oral glucose tolerance test and continuous glucose monitoring to assess diabetes development in cystic fibrosis patients

Introduction: Patients with cystic fibrosis (CF) undergo a slow and progressive process toward diabetes. Oral glucose tolerance test (OGTT) is recommended to diagnose impaired glucose levels in these patients. Continuous glucose monitoring (CGM) measures glucose profiles under real-life conditions. Objective: To compare OGTT and CGM results in CF patients. Methods: Paired OGTT and 6-day CGM profiles (146.2 +/- 9.1 h/patient) were performed in 30 CF patients aged 10-18 years. Results: According to OGTT, 14 patients had normal glucose tolerance (NGT), 14 abnormal glucose tolerance (AGT), and two cystic fibrosis-related diabetes (CFRD). In 27 patients (13 NGT, 13 AGT, 1 CFRD), CGM showed glucose values ranging from 140 to 200 mg/dL during similar monitoring times (2%-14% with NGT, 1%-16.9% with AGT, and 3% with CFRD). Glucose peak levels >= 200 mg/dL were seen in seven patients (3 NGT, 3 AGT, 1 CFRD). According to CGM, two patients had all glucose values under 140 mg/dL (1 NGT, 1 AGT). Seventeen patients had glucose levels ranging from 140 to 200 mg/dL (10 NGT, 6 AGT, 1 CFRD). Ten patients (3 NGT, 7 AGT) had glucose values >= 200 mg/dL for <= 1% of the monitoring time and one (CFRD) for >1% of the monitoring time. Conclusions: OGTT results did not agree with those of the CGM. CGM allows for diagnosis of glucose changes not detected by OGTT. Such changes may contribute to optimize pre-diabetes management in CF patients. (C) 2017 SEEN y SED. Published by Elsevier Espana, S. L. U. All rights reserved.