Mealtime insulin bolus adherence and glycemic control in adolescents on insulin pump therapy

Engelina Spaans, Kornelis J. J. van Hateren, Klaas H. Groenier, Henk J. G. Bilo, Nanne Kleefstra, Paul L. P. Brand

Poor self-management contributes to insufficient glycemic control in adolescents with type 1 diabetes (T1DM). We assessed the effects on glycemic control of adherence to self-measurement of blood glucose (SMBG) and insulin boluses in 90 adolescents with T1DM on insulin pump therapy over a 2-month period. We compared the number of insulin boluses and SMBGs around main meals to the "gold standard" of optimal diabetes management (SMBGs and a bolus before each main meal and SMBG before bedtime). The mean (95% CI) HbA1c levels were 2.9(1.7 to 4.0) mmol/mol lower for every additional insulin bolus and 3.1(1.6 to 4.5) mmol/mol lower for every additional SMBG. Patients performing SMBG and bolusing around each main meal had considerably lower HbA1c levels than those unable to do (95% CI for difference 4.3 to 10.4 mmol/mol and 11.5 to 20.1 mmol/mol respectively). For each additional mealtime bolus/day, the odds ratio of achieving target HbA1c levels of <58 mmol/mol was 6.73 (95% CI 2.94-15.38), after adjustment for gender, age, diabetes duration, and affective responses to SMBG in a multiple logistic regression model. Glycemic control in adolescents with T1DM on insulin pump therapy is strongly dependent on adherence to insulin boluses around mealtimes. What is Known: • In mixed groups of children and adolescents, insulin bolus frequency and self-monitoring of blood glucose (SMBG) frequency were determinants of HbA1c levels. • Adherence to insulin boluses and SMBG is particularly challenging in adolescents. What is New: • In adolescents on insulin pump therapy, each additional insulin bolus, particularly around mealtime, was significantly associated with approximately 3 mmol/mol lower HbA1c levels. • This beneficial effect of mealtime bolusing was strongest for the evening meal.