Résumé
Hypoglycemia remains a frequent consequence of insulin therapy, and nocturnal episodes are particularly concern-ing because they are often asymptomatic and unrecognized.In children with type 1 diabetes, our group previously showed that nocturnal hypoglycemia is common and maygo undetected [1]. Continuous glucose monitoring improves detection, but physiological changes preceding the glucosethreshold could offer additional information during sleep, when hypoglycemia is hardest to detect. Hypoglycemia activates the autonomic nervous system and counterregulatory pathways. Heart rate variability (HRV) is a noninvasive marker of autonomic regulation and has been reported to change during hypoglycemia in adults and children [2, 3]. However, pediatric data on the time course of HRV before nocturnal hypoglycemia is limited. We therefore examined high-resolution HRV trajectories before continuous glucose monitoring (CGM)-defined nocturnal hypoglycemia in children with type 1 diabetes.From January 2017 to April 2018, we conducted a prospective observational study in the home setting. Children and adolescents younger than 18 years with type 1 diabetes for at least 6 months were consecutively recruited from our outpatient clinic. Exclusion criteria were known cardiac disease and medication affecting cardiac function. The study was approved by the local ethics committee (BASEC 2016-01772), and written informed consent was obtained from participants aged 14 years or older and from parents or legal guardians.