Simplified Meal Bolus Strategies with Control-IQ+ Automated Insulin Delivery Are Safe and Effective in Adults with Type 2 Diabetes

Abstract

Objective: To characterize simplified meal bolus strategies in adults with insulin-treated type 2 diabetes using automated insulin delivery (AID). Research Design and Methods: In the 2IQP study, a 13-week randomized, controlled trial comparing Control-IQ+ AID to continuation of pre-study insulin regimen with continuous glucose monitoring, 201 participants in the AID arm were classified by meal bolus strategy. Glycemic outcomes were compared to baseline. Results: 68 participants' meal bolus strategies (33.8%) were classified as Carbohydrate Counting, 79 (39.3%) were classified as Preset Carbohydrate Amounts, 27 (13.4%) were classified as Fixed Insulin Doses, and 27 (13.4%) as Other Methods. All bolus strategies were associated with similar, significant improvements in HbA1c from baseline: -0.9% for Carbohydrate Counting (P < 0.001), -1.1% for Preset Carbohydrate Amounts (P < 0.001), -0.8% for Fixed Insulin Doses (P < 0.001), and -0.9% for Other Methods (P = 0.003). Hypoglycemia rates were low at baseline and remained low for all bolus strategies. As participants gained experience with the Control-IQ+ AID system, more participants opted to use a simplified bolus strategy in the second half of the study compared with the first half (63% vs. 52%). Conclusion: Simplified bolus strategies worked well for adults with type 2 diabetes using Control-IQ+ in the 2IQP trial. All bolus strategies led to substantial HbA1c improvements, without safety concerns.

Keywords: Control-IQ+; Tandem; bolus; carbohydrate counting; simplified meal bolus; t:slim X2; type 2 diabetes.