Objective: To assess the effect of three premeal timings of rapid-acting insulin on postprandial glucose excursions in type 1 diabetes.
Research design and methods: Ten subjects participated in a three-way randomized crossover trial. Mean ± SD age was 45.5 ± 12.1 years, A1C was 8.55 ± 1.50%, duration of diabetes was 23.8 ± 7.8 years, and duration of continuous subcutaneous insulin infusion therapy was 8.5 ± 6.1 years. Insulin aspart was administered at 30, 15, or 0 min before mealtime.
Results: Area under the curve was lower in the -15 stratum (0.41 ± 0.51 mmol/l/min) than that in the -30 stratum (1.89 ± 0.72 mmol/l/min, P = 0.029) and 0 stratum (2.11 ± 0.66 mmol/l/min, P = 0.030). Maximum glucose excursion was lower in the -15 stratum (4.77 ± 0.52 mmol/l) than that in the -30 (6.48 ± 0.76 mmol/l, P = 0.025) and 0 stratum (6.93 ± 0.76 mmol/l, P = 0.022). Peak glucose level was lower in the -15 stratum (9.26 ± 0.72 mmol/l) than that in the -30 stratum (11.74 ± 0.80 mmol/l, P = 0.007) and the 0 stratum (12.29 ± 0.93, P = 0.009). Time spent in the 3.5-10 mmol/l range was higher in the -15 stratum (224.5 ± 25.0 min) than that in the 0 stratum (90.5 ± 23.2 min, P = 0.001). There was no significant difference in occurrence of glucose levels <3.5 mmol/l between strata (P = 0.901).
Conclusions: Administration of rapid-acting insulin analogs 15 min before mealtime results in lower postprandial glucose excursions and more time spent in the 3.5-10.0 mmol/l range, without increased risk of hypoglycemia.