Glycemic Index, Extended Bolusing, and Diabetes Education in Insulin Pump Therapy (GLIDE: A Pilot Study)

Background: There is no published evidence on whether advanced bolus education affects outcomes in insulin pump-treated type 1 diabetes. We assess the feasibility of delivering a clinical education program on rates of digestion and bolusing, and to assess its preliminary impact. Methods: An interactive education session on glycemic index (GI), extended bolusing, and superbolusing was developed and assessed in a nonrandomized single-arm study for 12 weeks. Insulin pump-treated participants with type 1 diabetes were recruited. Glucose outcomes were assessed by blinded continuous glucose monitoring after the consumption of high-fat and high-GI test meal. The primary outcome measure was 8-h glucose area under the curve (AUC) after high-fat meals, before and after intervention. Secondary outcomes included time spent in hypoglycemia, quality of life, treatment satisfaction, HbA1c, frequency of use of extended boluses, and postprandial AUC. Results: Eleven participants completed the study [mean (SD) age 42.3 (12.8) years, baseline HbA1c 57.3 (10.0) mmol/mol, duration of diabetes 19.5 (9.9) years]. AUC for glucose after test meals did not differ significantly after education except for in the first 2 h after the high-GI meal [precourse 83.1 (0.23-88.9), postcourse 5.38 (-16.2 to 50.8)]. Percentage time spent in hypoglycemia (<3.9 and <3.3 mmol/L) fell at week 12 compared with baseline [5.8 (IQR 2.1-8.3) % to 4.3 (IQR 2.1-5.4) %, P  = 0.013, and 2.9 (IQR 1.2-3.9) % to 1.6 (IQR 0.7-2.4) %, P  = 0.029, respectively]. Conclusion: Delivering an education program to support advanced boluses is feasible and may reduce exposure to hypoglycemia. A further trial is required to confirm the findings.