ESPE Abstracts

Background: Development of cystic fibrosis–related diabetes (CFRD) is associated with worse pulmonary function, poorer nutritional status, more chest infections and increased mortality. In cystic fibrosis (CF) patients, abnormality of the 1 hour glucose during Glucose Tolerance test (GTT) is reported to be a better predictor of early CFRD and is associated with decline in pulmonary function compared to the 2-hour glucose level during GTT. We report a case series of 4 patients and their early detection and management of CFRD using Continuous Glucose Monitoring (CGM).

Methods: Our local practice since 2017 was to commence 2-weeks of CGM in children with CF who show a 1-hour glucose abnormality on the annual GTT screen. Depending on the CGM data, we initiate bolus prandial insulin initially as postprandial hyperglycaemia is usually the primary abnormality. We would then add basal insulin when fasting glucose becomes abnormal or insulin bolus requirements become significantly high. CGM is continued every month until blood glucose and insulin dosing is stable.

Results: Four patients with CF ages 6-15 years had impaired glucose at 1 hour GTT > 11.1 mmol. CGM was commenced in all 4 patients with targeted multidisciplinary approach. In 3 patients, sustained postprandial glucose abnormalities were detected. One patient also showed frequent elevated overnight, fasting and post-prandial glucose levels. CGM data guided the decision to start insulin, the choice of insulin regimen and insulin dosing. 1 patient commenced on multiple basal bolus insulin, 2 patients were commenced on prandial bolus insulin while one patient had regular intensive dietary advice with regular cappillary blood glucose monitoring. Nutritional status and FEV1 lung function improved in all 4 patients six months following targeted interventions. HbA1c improved in 3 patients who were commenced on insulin therapy. No side effects of hypoglycaemia was reported in the 3 patients who were commenced on insulin.

Conclusions: Abnormalities of glucose metabolism have a negative impact on morbidity and mortality in CF patients. Our study shows that early detection of glucose abnormalities using CGM and early MDT targeted intervention improves lung function and nutritional status. We recommend a pragmatic approach with insulin use to target initially postprandial glucose excursions and regular use of CGM to guide insulin dosing. Further studies are warranted on optimum timing of insulin initiation and the use of CGM in early detection and management of CFRD.