Contribution of postprandial versus interprandial blood glucose to HbA1c in type 1 diabetes on physiologic intensive therapy with lispro insulin at mealtime.

OBJECTIVE: To quantitate the contribution of postprandial blood glucose, which improves with the short-acting insulin analog lispro [Lys(B28),Pro(B29)] in type 1 diabetes, to the overall 24-h blood glucose concentration and the long-term HbA1c concentration under conditions of different postabsorptive blood glucose. RESEARCH DESIGN AND METHODS: A total of 24 type 1 diabetic patients on long-term intensive therapy with premeal human regular insulin (Hum-R) and bedtime NPH were randomly assigned to a continuation of Hum-R (group 1, n = 8), lispro (group 2, n = 8), or lispro + NPH (in variable proportions) administered at mealtime (group 3, n = 8) for 3 months, NPH administered at bedtime was continued in all three groups. Data from home blood glucose monitoring were collected, and a 24-h plasma glucose and insulin profile was obtained during a 2-day hospital visit to calculate areas under the postprandial glucose curve (3.5 h after breakfast, 3.5 h after lunch, and 3.0 h after dinner for a total of 10.0 h) and the postabsorptive blood glucose curve (the remaining 14.0 h out of 24.0 h) (AUC). Eight nondiabetic subjects were also studied. RESULTS: The substitution of Hum-R with lispro (group 2) resulted in lower postprandial blood glucose, but greater postabsorptive blood glucose (P