Literature
Clinical Pearls & Morning Reports
Published March 15, 2023
How did the hybrid closed-loop system compare with standard care in the trial by Wadwa et al.?
Wadwa et al. conducted a randomized trial that assessed the safety and efficacy of a hybrid closed-loop system as compared with standard care (either an insulin pump or multiple daily injections of insulin plus a continuous glucose monitor) in children with type 1 diabetes who were at least 2 years of age but younger than 6 years of age. Read the NEJM Original Article here.
Clinical Pearls
Q: What are the particular challenges of achieving glycemic targets in children with type 1 diabetes who are younger than 6 years of age?
A: The treatment of type 1 diabetes in children younger than 6 years of age is challenging because younger children receive small doses of insulin and have unpredictable food intake and unscheduled exercise activity. They also have less ability to articulate the need for treatment of hypoglycemia and more glycemic variability than older children. Consequently, most children in this age group do not meet glycemic targets.
Q: Can a hybrid closed-loop system of insulin delivery be safely and effectively initiated remotely?
A: Whether a hybrid closed-loop system of insulin delivery can be safely and effectively initiated remotely has been unclear in this age group. In this trial to assess the safety and efficacy of a closed-loop system in children who were 2 to younger than 6 years of age, the authors included the option of virtual training in the use of the device and virtual trial visits.
Morning Report Questions
Q: How did the hybrid closed-loop system compare with standard care in the trial by Wadwa et al.?
A: More than 80% of the training in the use of the closed-loop system and more than 90% of all the visits were conducted virtually. The duration of time that the glucose level was in the target range of 70 to 180 mg per deciliter was significantly longer — by approximately 3 hours per day — in patients who used the closed-loop system than in those in the standard-care group who used a continuous glucose monitor in conjunction with their usual insulin-delivery method. An increase in the mean time in range was observed within 1 day after the initiation of the closed-loop system, regardless of pretrial use of a pump or injections for insulin delivery, and this increase was observed during both daytime and nighttime. A beneficial effect of the closed-loop system was also seen in decreases in the percentage of time that the glucose level was above 250 mg per deciliter and in improved mean glucose and glycated hemoglobin levels. The incidence of hypoglycemia (as measured by continuous glucose monitoring) was low at baseline and did not differ between the trial groups during follow-up.
Q: What were some of the limitations of this trial?
A: The current trial was conducted in the United States during the Covid-19 pandemic. The trial design and protocol allowed for the conduct of the trial with virtual visits, without the usual requirement for in-person visits. As a consequence, recruitment of a broad group of patients from all over the United States, beyond the usual catchment area of each clinical site, was possible. However, even with this approach to recruitment, overrepresentation of families with higher socioeconomic status in the trial cohort may affect the generalizability of the results. An additional limitation was the trial period of only 13 weeks; it is unknown whether the observed treatment effect would be sustained over a longer period of time, as has been seen in older patients, but an extension trial is ongoing.