This study was performed to compare in real-life conditions the serum profile of insulin lispro (IL) after a subcutaneous (SC) injection, separate and mixed with insulin glargine (IG), using a sensitive radioimmunoassay for the specific determination of serum IL, and to evaluate the 12-wk effect of the mixture on glycemic control in young individuals with type 1 diabetes.
Research design and methods
The IL serum profiles were evaluated in 10 individuals with type 1 diabetes [age 21.9 ± 3.8 yr; diabetes duration 13.4 ± 4.9 yr; body mass index 25.1 ± 3.2 kg/m2; hemoglobin A1c (HbA1c) 8.3 ± 0.8%] during a mixed meal test (MMT) using IL and IG as separate (baseline) and mixed injection. The glycemic variability by continuous glucose monitoring system (CGMS) and the long-term diabetes control with HbA1c were also evaluated at baseline and after 12 wk mixing the two insulins.
The mixture of IL with IG decreased IL maximum serum concentration (CmaxIL) (29.4 ± 5.1 µU/mL vs. 13.7 ± 4.2 µU/mL; p = 0.03) without changing the time to reach the Cmax (TmaxIL), the IL area under the curve (AUCIL0-240), and the glucose dynamics during the MMT. The glucose variability and the HbA1c were equivalent to baseline after 12 wk mixing both insulins.
These data suggest that mixing IL with IG immediately before the SC injection decreases IL serum peak concentration without affecting the glycemic profile after 12 wk in this group with type 1 diabetes mellitus.