Page 333 - Glucose Monitoring Devices

340 CHAPTER 16 The dawn of automated insulin delivery

Other challenges that remain are not unique to closed-loop insulin delivery.
Whenever insulin is infused in the subcutaneous tissue there is a risk of infusion
set failures, which can lead to DKA if they go unrecognized. Algorithms that can
detect and alert users of infusion set failures would benefit all patients on insulin
pump therapy. Small studies investigating methods to tackle these issues have
been conducted [115e117].
For hybrid closed-loop systems to be adopted in toddlers and children with T1D
on very low insulin doses, there may be a need for diluted insulin that will allow for
fine-tuned insulin dose titrations in this extremely insulin sensitive population [118].
Previous studies using diluted insulin in hybrid closed-loop systems show promising
results, with reduced rates of hypoglycemia, a trend toward reduced glycemic
variability, and reduced interindividual variability in time to peak insulin action
with diluted insulin [119,120]. Yet, a more recent study could not corroborate this
in an outpatient trial where participants were randomized diluted or standard
concentration insulin [90]. Importantly, dosing frequency in that trial was in
15 min intervals, not the 5 min intervals that some systems use.
The duration that sensors and infusion sets can be worn can also pose additional
hassle to those with T1D. Extended wear of both components would decrease the
frequency of diabetes-related interruptions that occur. Finally, the person with
diabetes must not be forgotten in these technological advancements. Indeed, to
have a device integrate seamlessly into one’s life would require systems to allow
users to push as few buttons as possible, use their existing technology like their
cell phones to administer bolus insulin, and the physical footprint of these devices
should be minimized.

A bright future
Although tremendous progress has been made in the creation of closed-loop systems
and commercial availability of the first-generation hybrid closed-loop was a major
step, much remains to be done. Numerous academics, industry partners, and even
online communities seek to create more sophisticated automation of insulin delivery
(Table 16.1). Indeed, recent data from a randomized control trial of 14e71-year-old
participants using the Tandem Control IQ system showed that time in the range
between 70 and 180 mg/dL increased by 2.6 h (70% vs. 59%). Users were extremely
satisfied with the system based on technology acceptance questionnaires, had
minimal fingerstick (<0.5 per/day) throughout the study as the system uses the
Dexcom G6, and used automated insulin delivery 92% of the time. FDA approval
of the device is being sought.
Although commercial approval of new hybrid closed-loop systems is sought, a
movement by patients has created a Do it Yourself (DIY) diabetes community. Start-
ing with the creation of The Nightscout Project, when persons with diabetes and
their loved ones created methods to allow remote monitoring of sensor glucose
data, a strong online group has emerged. Moving from the viewing of sensor data
to creating insulin delivery algorithms and providing instructions to others on how
to create such DIY closed-loop systems has exponentially increased the community