Patients with type 1 diabetes mellitus (DM) may encounter situations in which meal size and content is unpredictable. In theory, postprandial injection of rapid-acting insulin analogues could prove more effective in achieving glucose control at such times because this treatment strategy could allow adjustment of insulin dose for the actual size of the meal consumed rather than being based on an estimate of what will be consumed.This study compared the postprandial glycemic control achieved with meal-related insulin aspart injected immediately before a meal with that injected immediately after a meal.This randomized, crossover study was conducted at Sansum Diabetes Research Institute, Santa Barbara, California. Adult patients with type 1 DM were enrolled. At study visit 1, patients were randomly assigned to inject insulin aspart 0 to 5 minutes before the start of the meal or immediately after the meal. The timing of injection relative to the meal was reversed at study visit 2. The meal-related dose was calculated based on the anticipated caloric and carbohydrate intake (preprandial injection) or actual calories and carbohydrates ingested (postprandial injection). Postprandial blood glucose concentrations were evaluated as markers of efficacy of postprandial aspart administration.Twenty patients were enrolled in the study (mean [SE] duration of DM, 22.5 [3.2] years; mean [SE] body mass index, 26.2 [1.0] kg/M2; age range, 22-82 years); 19 completed it. Total glucose AUC during the meal test was 22% less when insulin aspart was injected immediately before the study meal (mean [SE], 23,014 [1832] mg/dL.min) than when injected immediately after the meal (mean [SE], 29,535 [2243] mg/dL.min) (P0.001), but baseline-adjusted AUC was similar. Maximum mean (SD) glucose concentrations in the postprandial period were180 mg/dL, the current DM treatment goals specified by the American Diabetes Association (149.0 [9.9] mg/dL and 102.0 [9.2] mg/dL, following postprandial insulin aspart injection and preprandial injection, respectively; P0.001). There was variation in the number of calories consumed, but patients consumed a similar number of calories in the 2 treatment regimens. The frequency of postprandial hypoglycemia was comparable. Adjustment of postprandial insulin aspart dose for the actual meal size consumed maintained postprandial glucose concentrations within currently recommended treatment guidelines.Preprandial insulin aspart injection produced a better glucose profile and is preferred when conditions permit. However, both preprandial and postprandial insulin aspart administration achieved postprandial glucose concentrations within currently recommended treatment guidelines.
