Direct Comparison of Insulin Lispro and Aspart Shows Small Differences in Plasma Insulin Profiles After Subcutaneous Injection in Type 1 Diabetes

Two rapid-acting insulin analogs, lispro and aspart, are now available for clinical use (1). The aim of our study was to compare the plasma-insulin profiles of these analogs after subcutaneous injection in patients with type 1 diabetes. Fourteen patients with type 1 diabetes (six men and eight women, [mean ± SEM] 35.4 ± 3.3 years of age [range 22–59], HbA1c 7.3 ± 0.3% [reference range 3.2–5.4], BMI 24.7 ± 1.1 kg/m2, and diabetes duration 22.9 ± 2.6 years) were recruited for the study. Only two patients had measurable C-peptide levels (0.04 and 0.11 nmol/l). All patients were on multiple-injection therapy with a breakfast insulin dose of 11.1 ± 0.7 U (range 6–14) and no intermediate-acting insulin in the morning. The study was designed as a single blind randomized crossover study. On the first day, seven patients were randomized to insulin lispro (Humalog, U-100; Eli Lilly, Indianapolis, IN), and the other seven were randomized to insulin aspart (NovoRapid, U-100; Novo-Nordisk, Bagsveard, Denmark). On the second study day (5–21 days later), the patients received the alternative insulin analog. The patients continued their usual insulin treatment between the study days. All patients arrived to the clinic fasting. After an initial blood sampling, they were given 10 U s.c. of one of the insulins in the abdominal wall at 7:30 a.m. A standardized breakfast, which had an energy content of 418 kcal and a nutrient content of 21 g protein, 11 g …