Background: Hypoglycaemia is the most common and threatening complication in diabetic children. Nocturnal hypoglycaemia is mostly unrecognised and asymptomatic, but recurrent mild hypoglycaemia at night can lead to hypoglycaemia unawareness and reduced performance at daytime.
Aims: To evaluate frequency and duration of nocturnal hypoglycaemia in type 1 diabetic children and to identify risk factors for such events.
Patients/methods: 60 children with type 1 diabetes for >6 months were included. The data of 51 patients (29 m, 22 f, age 12.1 years, 2.417.6 years) were complete (>five nights recorded). For a 6-day period glucose was measured by continuous glucose monitoring (iPro, Medtronic) and physical activity was measured by accelerometry. Patients were asked to perform four capillary blood glucose measurements per day and to keep notes about bed time and wake-up time, carbohydrates and insulin. HbA1c was determined at the routine visit preceding the study. Nocturnal hypoglycaemia was defined as any glucose excursion <3.7 mmol/l during night time.
Results: 128 nocturnal hypoglycaemia were found, only eight of them being symptomatic. In 97 out of 297 nights one or more hypoglycaemia occurred. Duration of hypoglycaemia ranged from 5 to 665 min, 36% of the episodes lasted <1 h, 34% 13 h, 24% 36 h, and 6%, >6 h. Hypoglycaemia frequency was negatively correlated to HbA1c (−0.32*, also hypoglycaemia duration, −0.293*) and to physical activity (mean time in moderate to vigorous physical activity, 0.305*). Furthermore, low bedtime glucose was associated with higher risk of nocturnal hypoglycaemia. No association was found with insulin dosage, age, and diabetes duration.
Conclusion: Nocturnal hypoglycaemia is a relevant issue in diabetic children: it is frequent, mostly asymptomatic and often prolonged. Tight metabolic control, high activity and low bedtime glucose could be identified as possible risk factors. Cgms represents a helpful tool in detecting nocturnal hypoglycaemia and therefore optimising patient instruction and treatment.
20 - 22 Sep 2014
European Society for Paediatric Endocrinology