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

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. 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. 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]. 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.