Timing of bolus in children with type 1 diabetes using continuous subcutaneous insulin infusion (TiBoDi Study)

Background: Continuous subcutaneous insulin infusion is considered a safe and effective way to administer insulin in pediatric patients with type 1 diabetes, but achieving satisfactory and stable glycemic control is difficult. Several factors contribute to control, including fine-tuning the basal infusion rate and bolus timing. We evaluated the most effective timing of a pump-delivered, preprandial bolus in children with type 1 diabetes. Methods: We assessed the response of 30 children with type 1 diabetes to a standard meal after different timing of a bolus dose. Results: The glucose levels for 3 h after the meal were lower (i.e., closer to the therapeutic target of <140 mg/dL) when the bolus doses were administered 15 min or immediately before the meal, rather than after the meal. However, these differences were not statistically significant, except at the 1-h postprandial time point: bolus just after meal, 177 ± 71 mg/dL (9.83 ± 3.94 mmol/L); 15 min before meal, 136 ± 52 mg/dL (7.55 ± 2.89 mmol/L) (P = 0.044); and just before meal, 130 ± 54 mg/dL (7.22 ± 3.00 mmol/L) (P = 0.024). The area under the curve (AUC) (in mg/min) did not differ significantly with different bolus times, but the SD of the AUC was the lowest with the bolus given 15 min before the meal. Conclusions: These data support injection of the bolus before, rather than after, eating, even if the patient is hypoglycemic before meals.