Comparable glucose control with fast-acting insulin aspart versus insulin aspart using a second-generation hybrid closed-loop system during exercise.

Background We aimed to compare glucose control with FiAsp versus insulin aspart following moderate-intensity exercise (MIE) and high-intensity exercise (HIE) using a second-generation closed-loop (CL) system in people with type 1 diabetes. Materials and methods This randomised crossover study compared FiAsp versus insulin aspart over four sessions during MIE and HIE with CL insulin delivery by the MiniMed TM Medtronic Advanced hybrid CL system. Participants were randomly assigned FiAsp and insulin aspart each for six weeks and within each period performed, in random order, 40min MIE (~50% VO2max) and HIE (6x2min ~80% VO2max; 5min recovery). The primary outcome was continuous glucose monitoring (CGM) time in range (TIR, 3.9-10.0mmol/L) for 24h following exercise. Results Sixteen adults (nine male; age 48 [37, 57] years; HbA1c 7.0 [6.4, 7.2] %; duration diabetes 30 [17, 41] years) were recruited. In the 24h post-exercise, median TIR was >81%, time in hypoglycemia (<3.9mmol/L) was <4% and time in hyperglycemia (>10mmol/L) was <17% for both exercise conditions and insulin formations, with no significant differences between insulins (P>0.05). In the 2h post-exercise and overnight the TIR approached 100% for all conditions. Conclusions There were no differences in TIR during and 24h after MIE or HIE when comparing insulin aspart with FiAsp delivered by a second-generation CL system. Insulin formations with an offset in action greater than FiAsp are needed to provide a meaningful improvement in CL glucose control with exercise. Trial registration: ACTRN12619000469112 .