LAUSR

INTRODUCTION Continuous glucose monitoring (CGM) allows realtime interstitial glucose monitoring, therefore reducing the need for regular fingerprick blood testing. CGM also informs users of glucose trend data and alarms, which warns users of high or low blood glucose readings. There is a paucity of evidence on the use of CGM in patients without diabetes, but early data suggest that CGM can reduce episodes of hypoglycaemia in conditions such as hyperinsulinism and metabolic disorders. 2 Realtime CGM was shown to provide valuable insights into patterns of dysglycaemia, where rapid fluctuations were found in glucose levels in babies with hyperinsulinism. CGM used as an adjunct to clinical care was shown to support the management of persistent neonatal hypoglycaemia in the unit and limited the need for frequent and painful blood sampling in these babies. Congenital hyperinsulinism is the most frequent cause of severe, persistent hypoglycaemia in children and consists of persistent and transient forms. A number of different genetic defects cause persistent forms of hyperinsulinism, while transient hyperinsulinism often resolves completely in days or months. Severe, persistent and frequent hypoglycaemia is a potentially lifethreatening complication of congenital hyperinsulinism and may lead to permanent brain damage, presenting as significant developmental delay and/or mild to severe neurocognitive difficulties. Hypoglycaemia secondary to these conditions is serious, with almost 50% of children demonstrating neurological impairments as a result of recurrent hypoglycaemic events. The aim for treatment management is to reduce overall exposure to symptomatic and asymptomatic hypoglycaemia, to improve hypoglycaemia awareness and to reduce the fear of hypoglycaemia. The current standards of care for these patients are frequent observations and intermittent fingerprick blood testing. However, this provides no details of CGM trends with no alarm settings, resulting in patients and carers missing hypoglycaemia between infrequent fingerpick blood tests. CGM devices are currently only recommended by the National Institute of Clinical Excellence (NICE) in the UK for patients with type 1 diabetes as most studies have targeted a reduction in HbA1C rather than hypoglycaemia episodes as a clinical end point. While there is clear guidance from NICE for patients with diabetes with regard to whom CGM should be prescribed, funding pathways for CGM are complex. A national survey by the UK Association of Children’s Diabetes Clinicians reported that access to funding of CGM is highly variable, determined locally by clinical commissioning groups, some requiring individual funding applications, whereas others have local policies on who should access CGM devices. There is strong evidence to support the fact that there is improved detection of asymptomatic hypoglycaemia with CGM compared with intermittent blood fingerprick glucose monitoring for the population with type 1 diabetes. CGM technology has the potential to improve the management and quality of life for people with recurrent hypoglycaemia and healthcare professionals have a duty to support and provide the care needed to reduce the disease burden. The condition of hyperinsulinism and diabetes may be viewed as two sides of the same coin. CGM has traditionally been used in diabetes to optimise glycaemic variability and for those with hypoglycaemia unawareness. The goal for achieving normoglycaemia, avoidance of complications of significant hypoglycaemia and the fear of hypoglycaemia are similar aims in both conditions. In conditions such as hyperinsulinism, type 2 diabetes is also an associated diagnosis leading to hyperglycaemia management. Studies have also identified that the early hours of the day are a time of highest hypoglycaemia risk for patients with hyperinsulinism. In these circumstances, parents, carers and patients will not be able to routinely detect hypoglycaemia when they are asleep. From the patients’ perspective, the benefits of CGM were keenly felt by parents and carers in an unpublished UK Children’s Hyperinsulinism Charity (CHC) survey stating that it offered a safety net for missed hypoglycaemic events that were potentially life threatening, improved quality of life, and reduced their worries, anxieties and psychological burden. In many cases, parents have reported that CGM has avoided the need for prolonged hospitalisations and intense medical treatment as a result of hypoglycaemic events associated with the condition. This was in line with clinical research in children with diabetes where CGM has been shown to significantly reduce worry and fear of hypoglycaemia and improve the wellbeing of children and their parents. However, less than a third of patients have access to CGM, and many have stated that they simply cannot afford the ongoing cost to selffund CGM. A result of a British Society of Paediatric Endocrinology and Diabetes (BSPED) survey to clinicians found that a significant proportion of clinical teams were struggling to access funding for CGM, and funding streams were highly variable from region to region. The authors stress that CGM education will be needed to support its use in people with recurrent hypoglycaemia, including guidance and education on how to use CGM effectively, understanding its limitations, accuracy and making practical clinical decisions based on CGM metrics and downloads. For example, although CGM provides information about glucose variability and trends, CGM systems are variable and are less accurate when it comes to direct comparison with pointofcare testing of fingerprick blood glucose levels. Mean absolute relative difference (MARD) is a CGM metric which measures Paediatric Department, Southport and Ormskirk Hospital NHS Trust, Southport, UK Department of Women’s and Children’s Health, University of Liverpool, Liverpool, UK Edge Hill University, Ormskirk, UK UK Children’s Hyperinsulinism Charity, London, UK Leeds Teaching Hospitals NHS Trust, Leeds, UK Nottingham University Hospitals NHS Trust, Nottingham, UK