Missed Insulin Meal Boluses and Elevated Hemoglobin A_1c Levels in Children Receiving Insulin Pump Therapy

Objective. To identify possible causes of suboptimal glycemic control (ascertained by hemoglobin A_1c [HbA_1c] level) in youths using insulin pump therapy.

Methods. Forty-eight youths who were receiving insulin pump therapy for ≥6 months, and who were using insulin pumps and blood glucose meters with data that could be downloaded at our facility, are included in this cross-sectional study. Possible causes of suboptimal glycemic control were evaluated by using 4 information sources: 1) insulin pump data downloads; 2) glucose meter data downloads; 3) patient/family questionnaire about insulin bolusing habits, eating habits, exercise, and blood glucose testing habits; and 4) a physician questionnaire. Physicians completed the questionnaire during the patient interview after reviewing the downloaded information and discussing these results with the patient/family.

Results. The mean (± standard deviation) age of participants was 15.3 (±3.0) years (range: 7–20 years), and the mean (± standard deviation) duration of type 1 diabetes and continuous subcutaneous insulin infusion was 8.2 (±4.0) and 1.9 (±1.0) years, respectively. Patients who missed <1 bolus per week had a mean (95% confidence interval) HbA_1c level of 8.0% (7.7, 8.3), whereas those who missed ≥1 mealtime boluses per week had a mean HbA_1c level (95% confidence interval) of 8.8% (8.6, 9.1). No significant relationships were found between HbA_1c levels in males and females, the amount of exercise per week, or bolusing before insulin pump disconnection for exercise. Although not significant, a trend was found for those who missed <1 bolus per week to perform more blood glucose tests per day and for those who bolused before a meal rather than after to have lower HbA_1c levels. Significant correlations were found between HbA_1c levels and the number of missed mealtime boluses per week (r = .414) and mean blood glucose levels (r = .70).

Conclusion. Missed mealtime insulin boluses seem to be the major cause of suboptimal glycemic control in youths with diabetes receiving continuous subcutaneous insulin infusion therapy.