medwireNews: A fully closed-loop insulin delivery system markedly increases time in range (TIR) for people with insulin-treated type 2 diabetes, shows a small randomized crossover trial.
The team from Cambridge in the UK used the fully closed-loop CamsAPS HX system, previously tested in inpatients with type 2 diabetes, because it avoided the need to train the study participants in carbohydrate counting to give mealtime insulin boluses.
Presenting the findings at the 58th EASD Annual Meeting in Stockholm, Sweden, Charlotte Boughton (University of Cambridge) reported that the 26 study participants in the intention-to-treat analysis remained within the blood glucose target of 3.9–10.0 mmol/L (70–180 mg/dL) for an average of 66.3% of the time in the 8-week period they were using the closed-loop system.
And during the 8 weeks they used standard insulin therapy (with a masked continuous glucose monitor), their TIR averaged 32.3%, with the difference between the two periods amounting to an additional 8.5 hours/day within range with closed-loop delivery.
The study participants were an average age of 59 years, with a baseline glycated hemoglobin (HbA1c) of 9.0% (75 mmol/mol). They had an average diabetes duration of 17.5 years and had been taking insulin for an average of 8.5 years. Just three people had previously used continuous glucose monitoring.
The improvement in TIR with closed-loop insulin delivery was entirely due to a reduction in the time spent in hyperglycemia, which was 35.2 percentage points less with closed-loop versus standard insulin treatment. There were also significantly greater reductions in average glucose levels and HbA1c.
This did not come at the expense of more time in hypoglycemia, which averaged 0.44% and 0.08% with closed-loop and standard treatment, respectively.
But in contrast with studies of people with type 1 diabetes, the total daily insulin dose in these study participants with type 2 diabetes was numerically higher with closed-loop than standard treatment, averaging 108 versus 84 U/day.
Also, glucose levels tended to be relatively high at night rather than being at their lowest during these hours as is commonly seen in people with type 1 diabetes, and Boughton speculated that this could be due to differences in eating patterns.
Nevertheless, she reported that “almost all” of the study participants individually had an improved TIR during the closed-loop versus the standard treatment periods, and the proportion of time spent in closed-loop mode averaged 92.3%, “which shows high acceptability and usability of the system.”
All participants said they were happy to have their blood glucose controlled by the closed-loop system and all but two felt it reduced the amount of time they spent managing their diabetes.
The majority felt less worried about glucose control when using the system and most slept better at night, although a small number did not, which the presenter said “probably relates to the alarms” from the continuous glucose monitor.
Concluding, Boughton highlighted the small size of the study and the almost completely White population, and stressed the need for larger studies to ensure generalizability and determine cost-effectiveness.
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