ESPE Abstracts

Introduction: Congenital hyperinsulinism (CHI) is the commonest cause of severe hypoglycaemia in early childhood but glycaemic characterisation remains scarce. Continuous glucose monitoring (CGM) offers a deep understanding of glycaemic control to understand disease burden, individualise patient care and inform therapeutic trials in CHI. Preliminary studies suggest inadequate accuracy and no efficacy of standalone CGM to reduce hypoglycaemia. Provision is historically restricted to those with severe disease; thus performance of CGM and family experiences have only been described in a limited and biased cohort.

Methods: We aimed to report CGM data in an unbiased cohort of British patients during a year-long prospective study. Primary objectives were: 1. Determine baseline glycaemic characteristics 2. Evaluate hypoglycaemia trends and patterns 3. Understand families’ experiences and opinions of CGM Eligible patients had a diagnosis of CHI and were cared for at a specialist centre. Dexcom G6™ CGM consumables were provided for 12 months. Self-monitoring blood glucose (SMBG) with a Contour Next One™ glucometer was done at least twice a day and to confirm CGM hypoglycaemia. Ten months from study start, all patients were sent a questionnaire to report their experiences of CGM.

Results: Of the 49 patients recruited, 45 used CGM (35 CGM naïve). Mean (range) age was 6 years (2 months – 17 years) and 24 patients (53%) had a genetic diagnosis of CHI. The accumulated 2.7million CGM data points confirmed an increased hypoglycaemia risk in the early morning (0300–070H) with no longitudinal reduction in hypoglycaemia over 12 months. When paired with 17,500 SMBG values, CGM accuracy was poor; values differed by a mean of 25% (1mmol/L) from SMBG. Dissatisfaction with long-term CGM use was high, with 50% of patients discontinuing use. Questionnaires received from 43/46 parents and 9/9 patients identified pain and accuracy as primary reasons for discontinuation. CGM use reduced anxiety scores of parents but increased those of patients. In response to questionnaires, 80% of parents reported gaining understanding of hypoglycaemia patterns and trends from their CGM, suggesting CGM may inform changes in behaviour and routine with continued use.

Conclusions: Our large, prospective dataset of unblinded CGM in an unbiased selection of British CHI patients confirmed earlier findings of early-morning hypoglycaemia risk. CGM without interpretive support failed to reduce hypoglycaemia over an extended period, with dissatisfaction leading to significant discontinuation from long-term use. Future CGM use in CHI should focus on short-term provision to selected groups, accompanied by structured CGM education.