Optimized Mealtime Insulin Dosing for Fat and Protein in Type 1 Diabetes: Application of a Model-Based Approach to Derive Insulin Doses for Open-Loop Diabetes Management

OBJECTIVE To determine insulin dose adjustments required for coverage of high-fat, high-protein (HFHP) meals in type 1 diabetes (T1D). RESEARCH DESIGN AND METHODS Ten adults with T1D received low-fat, low-protein (LFLP) and HFHP meals with identical carbohydrate content, covered with identical insulin doses. On subsequent occasions, subjects repeated the HFHP meal with an adaptive model-predictive insulin bolus until target postprandial glycemic control was achieved. RESULTS With the same insulin dose, the HFHP increased the glucose incremental area under the curve over twofold (13,320 ± 2,960 vs. 27,092 ± 1,709 mg/dL ⋅ min; P = 0.0013). To achieve target glucose control following the HFHP, 65% more insulin was required (range 17%–124%) with a 30%/70% split over 2.4 h. CONCLUSIONS This study demonstrates that insulin dose calculations need to consider meal composition in addition to carbohydrate content and provides the foundation for new insulin-dosing algorithms to cover meals of varying macronutrient composition.