Efficacy of Carbohydrate Supplementation Compared With Bolus Insulin Dose Reduction Around Exercise in Adults With Type 1 Diabetes: A Retrospective, Controlled Analysis

Objectives: Individuals with type 1 diabetes try to manage the risk of exercise-induced hypoglycemia by either pre-exercise/pre-meal bolus insulin dose reductions and/or consuming additional carbohydrates during exercise. Both strategies have proven to be effective in offsetting hypoglycemia, but it remains unclear which one is more beneficial. The aim of this study was to assess the efficacy of carbohydrate supplementation vs bolus insulin dose reduction in prevention of hypoglycemia during moderate-intensity exercise in those with type 1 diabetes. Methods: This investigation was a retrospective, controlled analysis of 2 independent clinical trials. All participants performed continuous, moderate-intensity cycle ergometer exercise for ∼45 minutes. Two therapy management groups and a control group were compared. Group A was supplemented with 15 to 30 g carbohydrates at a glycemic threshold of 7.0 mmol/L during exercise, group B reduced their individual bolus insulin dose by 50% with their last meal before exercise and group C served as a control. Results: No hypoglycemic events occurred in group A, whereas 4 events were recorded in groups B (p=0.02) and C (p=0.02). Conclusions: Carbohydrate supplementation was superior to bolus insulin reduction for prevention of hypoglycemia during exercise in people with type 1 diabetes.