Safety of new algorithms for premeal insulin boluses in high glycaemic index meals in persons with type 1 diabetes mellitus using insulin pumps.

Aims: Consumption of glucose or foodstuffs with high glycaemic index (GI) in persons with type 1 diabetes mellitus (PWD1) is a hot topic in present diabetology. The aim of our pilot prospective study was to assess the efficiency of empirically suggested simple algorithms for premeal boluses in PWD1 using insulin pumps and continuous glucose monitoring (CGM).

Methods: Six PWD1 (aged 46.2+/-15.09 y, diabetes duration 14.5+/-9.65 y, HbA1c/IFCC 6.3+/-1.59%, BMI 23.6+/-1.67 kg/m(2), mean+/-SD) on insulin pumps Paradigm 522/722 with RT-CGMS sensors (Medtronic MiniMed, Northridge, CA) underwent a 12-week CGM. In one week, subjects consumed 50 g of carbohydrates in eleven alternative meals (rice squares, dark chocolate, white bread, honey, glucose, ravioli with meat and Eidam cheese, mashed potatoes with fish fingers, apricot dumplings with butter, spa waffles, spalta squares, and tomato soup with pasta) eaten for breakfasts, lunches, snacks and dinners in order to calculate their GI. The insulin boluses were adjusted according to empirically defined algorithms. Average glucose levels and daily insulin doses over three one-week periods (before testing, testing and after testing) were compared.

Results: During the observational period, the weekly averages of glucose levels (9.1+/-2.33 mmol/l vs. 9.2+/-2.30 mmol/l vs. 9.0+/-2.43 mmol/l, respectively) and daily insulin doses (39.1+/- 8.14 IU/d vs. 39.7+/-10.7 IU/d vs. 38.6+/-9.97 IU/d, respectively) were similar. One-week consumption of high GI foodstuffs had only a negligeable effect on average glucose levels.

Conclusion: The suggested algorithms for premeal insulin boluses appear to limit the risk of potential hyperglycaemia resulting from intake of high GI foodstuffs.