Timing of Meal Insulin Boluses to Achieve Optimal Postprandial Glycemic Control in Patients with Type 1 Diabetes

This study determined the optimal timing of insulin bolus administration in relation to meal consumption in adolescents and adults with type 1 diabetes.Twenty-three subjects participated in this crossover study consisting of three treatment arms: delivering an insulin glulisine bolus by insulin pump 20 min prior to a meal ("PRE"), immediately before the meal ("START"), and 20 min after meal initiation ("POST"). Blood glucose levels were measured every 30 min for a total of 240 min post-meal initiation. Mean blood glucose levels at 1 and 2 h after meal initiation, blood glucose area under the curve (AUC), and maximum blood glucose levels were analyzed.At both 60 and 120 min after meal initiation, the PRE arm showed significantly lower glycemic excursions than the START arm (P = 0.0029 and 0.0294, respectively) and the POST arm (P = 0.001 and 0.0408, respectively). Glycemic AUC was significantly less in the PRE arm versus both the START and POST arms (159.5 +/- 58.9 mg/dL vs. 187.0 +/- 43.1 mg/dL [P = 0.0297] and 184.5 +/- 33.2 mg/dL [P = 0.0463], respectively). Peak blood glucose levels were significantly lower in the PRE arm compared to the START arm (P = 0.0039) and the POST arm (P = 0.0027).A bolus of rapid-acting insulin 20 min prior to a meal results in significantly better postprandial glucose control than when the meal insulin bolus is given just prior to the meal or 20 min after meal initiation.