More youths with type 1 diabetes meet time-in-range goal with hybrid closed-loop system
The percentage of youths with type 1 diabetes spending at least 70% time in range more than doubled after 3 months of using a hybrid closed-loop insulin delivery system, according to a study published in Diabetes Technology & Therapeutics.
“The Control-IQ system can significantly improve time in range between 70 mg/dL and 180 mg/dL, bringing it closer to the [American Diabetes Association] goal of 70%,” Laurel H. Messer, PhD, RN, assistant professor of pediatrics at the Barbara Davis Center for Diabetes, University of Colorado Anschutz School of Medicine, told Healio. “This is a huge win for children and adolescents, who particularly struggle with glycemic control.”
Messer and colleagues conducted a prospective observational study of 191 youths with type 1 diabetes who began using the t:slim X2 insulin pump with Control-IQ technology (Tandem Diabetes) between January and November 2020 (median age, 14 years; 47.4% female; 87.8% white). Age, sex, race/ethnicity, insurance status and previous insulin delivery were obtained at enrollment from electronic health records. Glycemic and system data were collected from the Control-IQ software for a 2-week period at baseline and 1, 3 and 6 months after device use began. Device use measures included time using the hybrid closed-loop automation, time wearing the device, daily insulin dose, number of meal boluses given per day, mean number of hours per night using sleep activity, and average number of uses of exercise activity. Glycemic data included time in range of 70 mg/dL and 180 mg/dL, time in hypoglycemia below 70 mg/dL, time in severe hypoglycemia with glucose of 54 mg/dL, time above range of 180 mg/dL, and mean sensor glucose.
Hybrid closed-loop increases time in range
The percentage of youths wearing the sensor increased from 85% at baseline to 90.3% at 3 months (P = .003). Sleep activity feature usage increased through 6 months, whereas the exercise activity feature was used less over time. The number of meal boluses was unchanged during the study. The percent of time youths used the Control-IQ automation stayed at 86% or higher at all time points, and only seven participants discontinued use of the system at 6 months.
Time in range increased from 57% at baseline to 68.1% at 3 months and was sustained at 66.2% at 6 months (P < .001). The proportion of participants with a time in range of better than 70% increased from 23.5% at baseline to 47.8% at 3 months and was sustained at 46.7% at 6 months (P < .001). The mean glucose management indicator improved from 7.5% at baseline to 7.1% at 3 months and was sustained at 7.2% at 6 months (P < .001). The percentage of youths reaching a glucose management indicator goal of less than 7% increased from 26.5% at baseline to 43.9% at 3 months and was sustained at 41.1% at 6 months (P < .001).
Time in range differs by HbA1c
Time spent in hypoglycemia at less than 70 mg/dL decreased from baseline to 3 months and 6 months, although it remained below the target goal of less than 4% time below range. There was no change in time spent in serious hypoglycemia with glucose of less than 54 mg/dL.
Time in range differed according to baseline HbA1c. Those with a baseline HbA1c of 9% or greater had the largest improvement in time in range over 6 months. Youths with an HbA1c greater than 9% or between 7% and 9% at baseline had improvements in glucose management indicator at 6 months, but there was no change for those with an HbA1c less than 7%.
“A lot of devices and therapies show efficacy in structured clinical trials, but the real world is different,” Messer said. “It is encouraging that the Control-IQ system performed well in the real world as well, especially in children and adolescents.”
Messer said longer-term studies are needed to see whether glycemic improvements continue beyond 6 months.
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Laurel H. Messer, PhD, RN, can be reached at firstname.lastname@example.org.