First Accuracy and User-Experience Evaluation of New Continuous Glucose Monitoring System for Hypoglycemia Due to Hyperinsulinism.

INTRODUCTION: Patients with congenital hyperinsulinism (HI) require constant glucose monitoring to detect and treat recurrent and severe hypoglycemia. Historically, this has been achieved with intermittent self-monitoring blood glucose (SMBG), but patients are increasingly using continuous glucose monitoring (CGM). Given the rapidity of CGM device development, and increasing calls for CGM use from HI families, it is vital that new devices are evaluated early. METHODS: We provided two months of supplies for the new Dexcom G7 CGM device to 10 patients with HI who had recently finished using the Dexcom G6. Self-monitoring blood glucose was performed concurrently with paired readings providing accuracy calculations. Patients and families completed questionnaires about device use at the end of the two-month study period. RESULTS: Compared to the G6, the G7 showed a significant reduction in mean absolute relative difference (25%-18%, P < .001) and in the over-read error (Bland Altman +1.96 SD; 3.54 mmol/L to 2.95 mmol/L). This resulted in an improvement in hypoglycemia detection from 42% to 62% (P < .001). Families reported an overall preference for the G7 but highlighted concerns about high sensor failure rates. DISCUSSION: The reduction in mean absolute relative difference and over-read error and the improvement in hypoglycemia detection implies that the G7 is a safer and more useful device in the management of hypoglycemia for patients with HI. Accuracy, while improved from previous devices, remains suboptimal with 40% of hypoglycemia episodes not detected.

Standardised practices in the networked management of congenital hyperinsulinism: a UK national collaborative consensus.

Congenital hyperinsulinism (CHI) is a condition characterised by severe and recurrent hypoglycaemia in infants and young children caused by inappropriate insulin over-secretion. CHI is of heterogeneous aetiology with a significant genetic component and is often unresponsive to standard medical therapy options. The treatment of CHI can be multifaceted and complex, requiring multidisciplinary input. It is important to manage hypoglycaemia in CHI promptly as the risk of long-term neurodisability arising from neuroglycopaenia is high. The UK CHI consensus on the practice and management of CHI was developed to optimise and harmonise clinical management of patients in centres specialising in CHI as well as in non-specialist centres engaged in collaborative, networked models of care. Using current best practice and a consensus approach, it provides guidance and practical advice in the domains of diagnosis, clinical assessment and treatment to mitigate hypoglycaemia risk and improve long term outcomes for health and well-being.

Clustering of Hypoglycemia Events in Patients With Hyperinsulinism: Extension of the Digital Phenotype Through Retrospective Data Analysis.

BACKGROUND: Hyperinsulinism (HI) due to excess and dysregulated insulin secretion is the most common cause of severe and recurrent hypoglycemia in childhood. High cerebral glucose use in the early hours results in a high risk of hypoglycemia in people with diabetes and carries a significant risk of brain injury. Prevention of hypoglycemia is the cornerstone of the management of HI, but the risk of hypoglycemia at night or the timing of hypoglycemia in children with HI has not been studied; thus, the digital phenotype remains incomplete and management suboptimal. OBJECTIVE: This study aims to quantify the timing of hypoglycemia in patients with HI to describe glycemic variability and to extend the digital phenotype. This will facilitate future work using computational modeling to enable behavior change and reduce exposure of patients with HI to injurious hypoglycemic events. METHODS: Patients underwent continuous glucose monitoring (CGM) with a Dexcom G4 or G6 CGM device as part of their clinical assessment for either HI (N=23) or idiopathic ketotic hypoglycemia (IKH; N=24). The CGM data were analyzed for temporal trends. Hypoglycemia was defined as glucose levels <3.5 mmol/L. RESULTS: A total of 449 hypoglycemic events totaling 15,610 minutes were captured over 237 days from 47 patients (29 males; mean age 70 months, SD 53). The mean length of hypoglycemic events was 35 minutes. There was a clear tendency for hypoglycemia in the early hours (3-7 AM), particularly for patients with HI older than 10 months who experienced hypoglycemia 7.6% (1480/19,370 minutes) of time in this period compared with 2.6% (2405/92,840 minutes) of time outside this period (P<.001). This tendency was less pronounced in patients with HI who were younger than 10 months, patients with a negative genetic test result, and patients with IKH. Despite real-time CGM, there were 42 hypoglycemic events from 13 separate patients with HI lasting >30 minutes. CONCLUSIONS: This is the first study to have taken the first step in extending the digital phenotype of HI by describing the glycemic trends and identifying the timing of hypoglycemia measured by CGM. We have identified the early hours as a time of high hypoglycemia risk for patients with HI and demonstrated that simple provision of CGM data to patients is not sufficient to eliminate hypoglycemia. Future work in HI should concentrate on the early hours as a period of high risk for hypoglycemia and must target personalized hypoglycemia predictions. Focus must move to the human-computer interaction as an aspect of the digital phenotype that is susceptible to change rather than simple mathematical modeling to produce small improvements in hypoglycemia prediction accuracy.

Longitudinal Auxological recovery in a cohort of children with Hyperinsulinaemic Hypoglycaemia.

BACKGROUND: Hypoglycaemia due to hyperinsulinism (HI) is the commonest cause of severe, recurrent hypoglycaemia in childhood. Cohort outcomes of HI remain to be described and whilst previous follow up studies have focused on neurodevelopmental outcomes, there is no information available on feeding and auxology. AIM: We aimed to describe HI outcomes for auxology, medications, feeding and neurodevelopmental in a cohort up to age 5 years. METHOD: We reviewed medical records for all patients with confirmed HI over a three-year period in a single centre to derive a longitudinal dataset. RESULTS: Seventy patients were recruited to the study. Mean weight at birth was - 1.0 standard deviation scores (SDS) for age and sex, while mean height at 3 months was - 1.5 SDS. Both weight and height trended to the population median over the follow up period. Feeding difficulties were noted in 17% of patients at 3 months and this reduced to 3% by 5 years. At age 5 years, 11 patients (15%) had neurodevelopmental delay and of these only one was severe. Resolution of disease was predicted by lower maximum early diazoxide dose (p = 0.007) and being born SGA (p = 0.009). CONCLUSION: In a three-year cohort of HI patients followed up for 5 years, in spite of feeding difficulties and carbohydrate loading in early life, auxology parameters are normal in follow up. A lower than expected rate of neurodevelopmental delay could be attributed to prompt early treatment.

Delayed Resolution of Feeding Problems in Patients With Congenital Hyperinsulinism.

Background: Congenital Hyperinsulinism (CHI) is the most common cause of recurrent and severe hypoglycaemia in childhood. Feeding problems occur frequently in severe CHI but long-term persistence and rates of resolution have not been described. Methods: All patients with CHI admitted to a specialist center during 2015-2016 were assessed for feeding problems at hospital admission and for three years following discharge, through a combination of specialist speech and language therapy review and parent-report at clinical contact. Results: Twenty-five patients (18% of all patients admitted) with CHI were prospectively identified to have feeding problems related to sucking (n = 6), swallowing (n = 2), vomiting (n = 20), and feed aversion (n = 17) at the time of diagnosis. Sixteen (64%) patients required feeding support by nasogastric/gastrostomy tubes at diagnosis; tube feeding reduced to 4 (16%) patients by one year and 3 (12%) patients by three years. Feed aversion resolved slowly with mean time to resolution of 240 days after discharge; in 15 patients followed up for three years, 6 (24%) continued to report aversion. The mean time (days) to resolution of feeding problems was lower in those who underwent lesionectomy (n = 4) than in those who did not (30 vs. 590, p = 0.009) and significance persisted after adjustment for associated factors (p = 0.015). Conclusion: Feeding problems, particularly feed aversion, are frequent in patients with CHI and require support over several years. By contrast, feeding problems resolve rapidly in patients with focal CHI undergoing curative lesionectomy, suggesting the association of feeding problems with hyperinsulinism.

Complexities in the medical management of hypoglycaemia due to congenital hyperinsulinism.

Congenital Hyperinsulinism (CHI) is a rare disease of hypoglycaemia but is the most common form of recurrent and severe hypoglycaemia causing brain injury and neurodisability in children. The management of CHI is complex due to the limited choice of medications, all with a limited therapeutic window, often lacking efficacy and associated with serious side effects. The therapeutic strategy in CHI is to recognize and treat hypoglycaemia promptly, thereby optimizing long-term neurological outcomes; this should be achieved through individualized treatment plans that deliver glycaemic stability while minimizing side effects. Further, such a strategy should consider the likelihood of reduction in disease severity over time, with dose adjustments and medication withdrawal as indicated to optimize both safety and tolerability. The option for pancreatic surgery should also be considered in specific circumstances as appropriate for the patient's best long-term interests.

Retrospective review of Synacthen testing in infants.

BACKGROUND: A subnormal cortisol response (30 min level (C30min)<550 nmol/L) to synthetic adrenocorticotrophic hormone/Synacthen test (SDST) in all infants does not necessarily indicate underlying or persistent hypothalamic-pituitary-adrenal axis pathology. METHODS: We retrospectively evaluated the diagnoses and outcomes in 68 infants who had a SDST at age <6 months from 2011 to 2014. RESULTS: 29 (43%) infants had a subnormal SDST. Causative pathology was identified in 9/29 (31%). In 20/29 (69%) with no identified pathology, repeat SDST was normal in 18/20 (90%) at median age 0.6 (range 0.1-3.2) years but persistently subnormal in 2. Those with a transient abnormality were more likely to be small for gestational age (P=0.03) and had higher initial SDST C30min (390 nmol/L vs 181 nmol/L, P=0.01) than those with pathology. CONCLUSION: Specific aetiology can be identified in a third of infants with a subnormal SDST. When the aetiology remains elusive, adrenal function should be reassessed as the problem can be transient.

The challenge of delivering endocrine care and successful transition to adult services in adolescents with congenital adrenal hyperplasia: experience in a single centre over 18 years.

BACKGROUND: Congenital adrenal hyperplasia (CAH) has implications throughout a patient's life. The challenges of organizing transition from paediatric to adult care in endocrinology are recognized. OBJECTIVE: To evaluate whether young people with CAH have been successfully transitioned from paediatric care to specialist adult services and the influence of the introduction of a Young Person Clinic (YPC) where the young person is introduced to the adult endocrinologist. DESIGN, PATIENTS AND MEASUREMENTS: Patients aged 16+ years with CAH who had attended the adrenal clinic at Royal Manchester Children's Hospital between 1992 and 2009 were identified. Clinical information, attendance data in paediatric and adult services were obtained from patient records and the electronic appointment system. RESULTS: A total of 61 patients (27 men) were identified. Thirty-six patients were referred to specialist adult services from the paediatric service; eighteen of these (50%) were lost to follow-up (two were never offered an appointment). Only 53% of the whole group attended their first new and subsequent second appointment (i.e. good early attenders). There was no difference in engagement with adult services in those who transitioned through the YPC. Good early attenders were less likely to get lost to follow-up compared with poor early attenders (11-33% lost to follow-up compared with 63-71%). CONCLUSIONS: Half of all young people with CAH referred to specialist adult services are no longer attending. Introducing the adult endocrinologist prior to transfer had no positive effect on engagement with adult services. Attendance at the first two appointments in the adult services should be seen as an indicator of 'reasonable' engagement.

Gender dichotomy in long term growth trajectories of children with 21-hydroxylase deficiency congenital adrenal hyperplasia.

AIM: To evaluate longitudinal growth in 21-hydroxylase deficiency congenital adrenal hyperplasia (CAH), factors contributing to this and outcome for BMI, weight (Wt) and height (Ht) in adolescence. METHODS: Multi-level longitudinal models were used to evaluate growth patterns of 45 salt wasters (SW) and 12 non-SW with CAH. RESULTS: Ht, Wt and BMI growth curves differed between SW and non-SW, and by gender. In contrast to SW and males, non-SW females showed a markedly different pattern with a progressive increase in Wt and BMI SDS over childhood and adolescence and only a slight gain in Ht SDS. BMI SDS remained above 0 after early childhood. Over the 15 years, the growth variables were negatively associated with fludrocortisone (FC) (shorter children were receiving larger doses) but not hydrocortisone (HC) doses nor FC and HC doses in the first year. CONCLUSION: The growth patterns in these children with CAH were influenced by age, gender, phenotype and FC treatment. There was a trend to increasing BMI from an early age, greater adiposity during childhood and females had disproportionately greater adiposity but shorter stature during adolescence. These patients therefore have a predisposition to obesity in childhood and later life independent of early corticosteroid treatment.