Predictors of glycaemic control and hypoglycaemia in children and adolescents with type 1 diabetes from NSW and the ACT

Abstract

Objectives: To audit glycaemic control and incidence of severe hypoglycaemia in children and adolescents with type 1 diabetes in New South Wales (NSW) and the Australian Capital Territory (ACT).

Design: A multicentre, population-based, cross-sectional study from 1 September to 31 December, 1999.

Participants: 1190 children and adolescents aged 1.2-15.8 years with type 1 diabetes, identified from three hospital-based paediatric diabetes units, four private city-based paediatric practices and 18 regional outreach clinics in NSW and the ACT.

Main outcome measures: HbA(1c) level and incidence of severe hypoglycaemia (defined by unconsciousness or seizures).

Results: The response rate was 67% (1190 of a target group of 1765). The median HbA(1c) level was 8.2% (interquartile range, 7.6%-9.1%). Significant predictors of HbA1c level in a multiple regression model were duration (b = 0.05; 95% CI, 0.02-0.07) and insulin dose/kg (b = 0.46; 95% CI, 0.27-0.66). At least one episode of severe hypoglycaemia in the previous three months was reported in 6.7%, and the rate of severe hypoglycaemia was 36/100 patient-years. Significant predictors of hypoglycaemia in a Poisson regression model were younger age (P = 0.03), male sex (P = 0.04), longer diabetes duration (P = 0.02), and > 3 daily insulin injections (P = 0.02), but not HbA(1c) level. Children with diabetes had higher BMI standard deviation scores compared with population standards, and those in the highest quartile of BMI standard deviation score were younger, had shorter diabetes duration and had higher HbA(1c) level.

Conclusions: Many children and adolescents with type 1 diabetes have suboptimal glycaemic control, placing them at high risk of developing microvascular complications. Those with longer diabetes duration are at increased risk of suboptimal glycaemic control and severe hypoglycaemia and should be targeted for interventional strategies.