<p><b>Objective</b></p>
<p>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. </p>
<p><b>Research Design and Methods</b></p>
<p>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).</p>
<p><b>Results</b></p>
<p>Twenty-five adults (52% male)
were recruited; median (IQR) age was 48 (37, 57) years, and HbA<sub>1c</sub> 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]; <i>p</i>=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]; <i>p</i>=0.003). There was no
ketoacidosis or severe hypoglycemia. </p>
<p><b>Conclusions</b></p>
<p>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%.</p>