Predictors of changing insulin dose requirements and glycaemic control in children, adolescents and young adults with Type 1 diabetes.

AIMS: To investigate trajectories of daily insulin dose requirements and glycaemic control in children, adolescents and young adults with Type 1 diabetes and to identify factors associated with changing insulin needs and deterioration in HbA .

METHODS: The sample was a dynamic cohort of 635 children, adolescents and young adults with Type 1 diabetes from one centre. Data from clinic visits occurring over 20 years (1993-2013) were extracted from medical records. From age 7-24 years, we evaluated HbA and insulin dose according to sex, insulin regimen and weight status.

RESULTS: Participants provided a mean ± sd of 10.7±4.3 years of insulin dose data and 12.0±4.6 years of HbA data. At first observation, the mean ± sd age was 10.0±2.6 years, diabetes duration was 2.8±2.1 years, insulin dose was 0.8±0.2 units/kg and HbA was 74±18 mmol/mol (8.9±1.6%). Insulin dose was higher in girls at ages 8-13 years (P<0.0001 to P<0.01), but higher in boys/young men at ages 16-21 years (P<0.0001 to P=0.04). HbA was higher in girls/young women at ages 16-24 years (P<0.0001 to P=0.01). Compared with injection therapy, pump therapy was associated with lower insulin dose at ages 8-24 years (P<0.0001 to P=0.03) and lower HbA at ages 8-22 years (P<0.0001 to P=0.005). HbA did not differ between overweight/obese and normal weight individuals, but overweight/obese individuals had higher insulin dose at ages 8-13 years (P<0.0001 to P=0.03).

CONCLUSIONS: This longitudinal assessment identifies clinically meaningful modifiable (e.g. insulin regimen) and non-modifiable (e.g. sex) factors predictive of insulin requirements and HbA levels in young people with Type 1 diabetes; anticipatory insulin adjustments may improve glycaemic control.