[Abnormal glucose tolerance in prepubertal patients with cystic fibrosis].

INTRODUCTION

Annual screening for abnormal glucose tolerance (AGT) with oral glucose test should begin by age 10 years in cystic fibrosis (CF) patients (Consensus-2010).

AIMS

To examine the frequency of AGT and its outcome in prepubertal CF patients and the changes in glycemic and nutritional status and lung function over the preceding year.

PATIENTS AND METHODS

Retrospective study of 19 prepubertal CF patients (68% males). All subjects underwent an oral glucose tolerance test (OGTT). Results were classified as: normal glucose tolerance (NGT) or AGT (impaired glucose tolerance [IGT], CF related diabetes [CFRD] or indeterminate glucose tolerance [INDET]). We analyzed: OGTT (glucose and insulin levels), nutritional status (BMI-SD) and lung function (forced spirometry). Statistical analysis was performed with SPSS program-version-15.0, non parametric tests.

RESULTS

Mean age at first OGGT: 8.5 years (5.8-9.8). Mean follow-up: 2 years (2-3). Initially, 47% patients had AGT and 53% NGT. In follow-up: 4/10 NGT patients developed AGT (3 IGT, 1 CFRD). Among initial AGT patients, of 4 INDET: 2 developed IGT, 1 CFRD. Mean age of AGT onset: 8.6 years (6.4-11.1). In 69% AGT patients a declining BMI-DS and/or lung function was found in the preceding year. In OGTTs performed, fasting and 2h AUC insulin levels were comparable between NGT and AGT; however, insulinogenic index was lower in AGT patients (p=.006). Insulin secretion was delayed in all patients.

CONCLUSIONS

The high frequency of AGT in prepubertal CF patients and their negative clinical impact supports the usefulness of an earlier glycemic screening.