Effect of age of infusion site and type of rapid-acting analog on pharmacodynamic parameters of insulin boluses in youth with type 1 diabetes receiving insulin pump therapy.

Objective: The purpose of this study was to examine the effect of type of insulin analog and age of insertion site on the pharmacodynamic characteristics of a standard insulin bolus in youth with type 1 diabetes receiving insulin pump therapy.
Research Design and Methods: Seventeen insulin pump-treated adolescents with type 1 diabetes underwent two euglycemic clamp procedures after a 0.2 unit/kg bolus of either insulin aspart or lispro on day 1 and day 4 of insulin pump site insertion. The glucose infusion rate (GIR) required to maintain euglycemia was the primary pharmacodynamic measure.
Results: There were no statistically significant differences in any of the pharmacodynamic parameters between aspart and lispro during day 1 and day 4. However, when the two groups were combined, time to discontinuation of exogenous glucose infusion, and time to half-maximal onset and offset of insulin action were observed significantly earlier during day 4 compared with day 1 (P = 0.03-0.0004), but the overall area under the GIR curve was similar on day 1 and day 4.
Conclusions: With both insulin aspart and lispro, there is an earlier peak and shorter duration of action with increasing duration of infusion site use, but overall insulin action is not affected.