medwireNews: A large real-world study shows improved glycemic outcomes for adults and children who initiate use of the Loop DIY automated insulin delivery system using community resources.
John Lum (Jaeb Center for Health Research, Tampa, Florida, USA) and co-researchers note that open-source closed-loop insulin delivery algorithms such as Loop are gaining popularity with people with type 1 diabetes, “with at least 9000 having used Loop.”
This study looked at 558 new users of Loop, who were aged between 1 and 71 years (average 23 years). Most of these people were White (91%), well educated, and affluent. The vast majority (90%) were using Loop with the Insulet Omnipod insulin pump, and most had used an artificial pancreas system in the past, predominantly the commercially available Medtronic 670G.
The researchers highlight the self-selected and “skewed” nature of the cohort, which “limits the generalizability of the results.”
They point out that most participants had glycated hemoglobin (HbA1c) levels below 7.0% (53 mmol/mol) before starting on Loop; the average was 6.8% (51 mmol/mol).
Nevertheless, the average time in range (70–180 mg/dL; 3.9–10.0 mmol/L) significantly improved during the first 6 months of using Loop, to 73% from a previous 67% based on continuous glucose monitoring (CGM) data.
The proportion of participants who were in range at least 70% of the time increased from 44% to 63%, with these improvements being evident from the first day of Loop use, the researchers report in Diabetes Technology & Therapeutics.
“The improvement in [time in range] during this observational study was similar in magnitude to that reported in randomized controlled trials of other closed-loop systems after accounting for differences among study cohorts in baseline HbA1c levels,” they write.
Improved glycemic control was seen for all ages and baseline HbA1c levels, and the benefits “appeared comparable” in people with moderate versus high incomes.
The incidence of severe hypoglycemia was 18.7 events per 100 person–years, which Lum and team say is higher than reported in other studies. They say this could reflect the study’s weekly text prompts to report severe hypoglycemia, the lack of close clinical oversight of participants due to the real-world design, or possibly a relatively hyperglycemia-avoidant cohort.
Nonetheless, this rate was a marked improvement over that reported for the 3 months prior to initiating Loop, and study participants had significant improvements in most hypoglycemia CGM variables.
The researchers note that the forthcoming commercial version of Loop “will rely on the data generated in this study to support FDA clearance.”
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Diabetes Technol Ther 2021; doi:10.1089/dia.2020.053