ESPE Abstracts

Background: Persistent hypoglycaemia is common in the newborn, due to prematurity or congenital hyperinsulinism (CHI) and is associated with the risk of poor neurodevelopmental outcome. Adequate monitoring is critical in prevention but is dependent on frequent blood sampling. Continuous glucose monitoring (CGM) is increasingly being used in children with type 1 diabetes mellitus who also are at risk from hypoglycemia, but use in neonatology remains limited. Previous studies have highlighted the potential of masked CGM to identify clinically silent episodes of transient hypoglycaemia in the newborn. We aimed to introduce real-time CGM to provide insights into patterns of dysglycaemia and to support the management of infants with persistent hypoglycemia.

Methods: This is a single centre retrospective study of real-time CGM use over a 4-year period in babies with persistent hypoglycaemia. We had used the mean absolute relative difference (MARD), Bland -Altman analysis and Clarke Error grid plots to explore the impact of CGM.

Results: CGMs were inserted in 14 babies: 8 term and 6 preterm infants, 9 with evidence of hyperinsulinism. The median age at first CGM insertion was 14 days (2-98 days), with a total of 224 days of data collected. A total of 1254 paired glucose values (CGM and blood) were available, and comparison gave a MARD of 11%. The CGM revealed marked fluctuations in glucose levels. There were 22 clinical episodes of hypoglycaemia (blood glucose <2.6 mmol/l) and sensitivity for detecting hypoglycaemia was 0.73, specificity 0.94, positive predictive value 0.17 and negative predictive value of 0.99. The CGM data showed that neonates with CHI tended to have greater SD (1.52±0.79 mmol/l vs 0.77±0.22 mmol/l, P = 0.07) compared to preterm infants.

Conclusion: The CGM data highlighted marked fluctuations in glucose levels in babies with CHI, in contrast to preterm babies, and therefore the challenges of preventing hypoglycaemia in these babies when using intermittent blood glucose levels alone. The low sensitivity despite high specificity of CGM for hypoglycaemia means CGM results in high numbers of false positives but could help to reduce the frequency of blood sampling during normoglycaemia.