Page 275 - Glucose Monitoring Devices

282 CHAPTER 14 Predictive low glucose suspend systems

of the PLGM feature was associated with a lower percentage of CGM
values 70 mg/dL and a lower percentage of values 240 mg/dL. For patients
switching from an LGS system to a PLGM system, the use of the PLGM system
was also associated with a decrease in the number of excursions 70 mg/dL
and 240 mg/dL. These findings are notable because they reflect a large number
of patients, using commercially available systems in the real world without
study-level supervision and seeing significant improvement in extreme glycemic
exposures. They are also important as they demonstrate a further reduction in
extremes when going from an LGS to PLGM system.
A multicenter randomized controlled trial in children and adolescents conducted by
Abraham compared the MiniMed 640G PLGM system against sensor-augmented
pump therapy (SAPT) in 154 children and adolescents over 6 months of use [48].
This study demonstrated a reduction in hypoglycemia exposure <63 mg/dL for
both groups with respect to baseline, though with a greater reduction in PLGM users
than SAPT users ( 1.4% vs. 0.4%, P <.0001). There was no difference in HbA1c
values at 6 months between the PLGM and SAPT groups (7.8 0.8% vs. 7.6 1.0%;
P ¼ .35). This study is important as it has a very strong design as a real-world multi-
center randomized controlled trial. In that context, the findings of the significant
reduction in hypoglycemia exposure for PLGM compared to a strong control arm
of SAPT provides a high level of support for the benefits of this technology.
The pivotal trial for the Tandem PLGS system was a multicenter randomized
controlled crossover trial comparing PLGS to SAPT among 103 adults, adolescents
and children [49]. This study demonstrated a 31% relative reduction in mean
time <70 mg/dL for PLGS compared to SAPT without an increase in percent
time >180 mg/dL. The findings from this study also demonstrated excellent system
usability with >90% active system time. This study is notable because the random-
ized crossover design allows for another strong comparison of PLGS versus SAPT
and the minimally supervised outpatient setting with broad patient age range allows
for generalizability of the study results further supporting the benefits of PLGS
technology.

Commercial devices
As it is imperative for clinicians to understand the function and tuning of commer-
cial automated systems, we present the commercially available PLGS systems here
using the CARE paradigm previously presented by our group (Table 14.2)[65]. In
January 2015, Medtronic announced the international launch of MiniMed 640G. The
components of MiniMed 640G (Medtronic, Northridge, California) are the MiniMed
640G insulin pump, Enlite Sensor, GuardianLink 2 transmitter and, SmartGuard
feature. The SmartGaurd feature includes a PLGM algorithm that, as described
earlier, suspends basal insulin delivery when the sensor glucose value is predicted
to reach below a preset low glucose limit within 30 min. Specifically, the system
suspends basal insulin when the predicted glucose is at or within 20 mg/dL of the