Fast-Acting Insulin Aspart Versus Insulin Aspart Using a Second-Generation Hybrid Closed-Loop System in Adults With Type 1 Diabetes: A Randomized, Open-Label, Crossover Trial

Objective

To evaluate glucose control using fast-acting insulin aspart (faster aspart) compared with insulin aspart (IAsp) delivered by the MiniMedä Advanced Hybrid Closed-Loop (AHCL) system in adults with type 1 diabetes.

Research Design and Methods

In this randomized, open-label, crossover study, participants were assigned to receive faster aspart or IAsp in random-order. Stages 1 and 2 comprised six-weeks in closed-loop; preceded by two-weeks in open-loop. This was followed by Stage 3, whereby participants changed directly back to the insulin formulation used in Stage 1 for one-week in CL. Participants chose their own meals except for two standardized meal tests; a missed and late meal bolus. Primary outcome was % sensor glucose time-in-range (TIR; 70-180mg/dL).

Results

Twenty-five adults (52% male) were recruited; median (IQR) age was 48 (37, 57) years, and HbA_1c 7.0% (6.6, 7.2) (53 [49, 55] mmol/mol). Faster aspart demonstrated greater overall TIR compared with IAsp (82.3% [78.5, 83.7] vs. 79.6% [77.0, 83.4], respectively; mean difference 1.9% [0.5, 3.3]; p=0.007). Four-hour PPG TIR was higher using faster aspart compared with IAsp for all-meals combined (73.6% [69.4, 80.2] vs. 72.1% [64.5, 78.5], respectively; median difference 3.5% [1.0, 7.3]; p=0.003). There was no ketoacidosis or severe hypoglycemia.

Conclusions

Faster aspart safely improved glucose control compared with IAsp in a well-controlled group of adults with type 1 diabetes using AHCL. The modest improvement mainly related to mealtime glycemia. Whilst the primary outcome demonstrated statistical significance, the clinical impact may be small given an overall difference in TIR of 1.9%.