Posters
Continuous glucose monitoring system
Francine Kaufman
Los Angeles, CA, USA
Introduction
There were two posters that presented data on the continuous glucose
monitoring system (CGMS) developed by MiniMed, Inc, of Sylmar, CA. The
first by Bode et al., entitled “Continuous Glucose Monitoring
Facilitates Sustainable Improvements in Glycemic Control ”explained
that CGMS allows for 288 blood glucose levels to be determined each day
and that the system can be worn for up to 72 hours. Bode et al. had
previously published that CGMS could be used to improve glycemia over a
5-week period. This was accomplished because patterns and trends could
be identified that allowed health care providers to change insulin
dosages, diets, or how high and low blood glucose values were treated.
Study design
The study design was as follows: 9 subjects with Type 1 diabetes who
were in “poor”control with HbA1c values > 8.5%, wore the CGMS for
two 1-week periods. After each sensor wear, adjustments were made as
dictated by the glucose results. HbA1c levels were repeated at 5 and 10
weeks during which time no additional therapy changes were made by the
health care team.
Results
The change in mean HbA1c was not accompanied by a change in mean insulin
dosage (p = 0.428) (Table II).
Conclusions
There was a significant decrease in mean HbA1c values as the result of
using the CGMS to alter the diabetes regimen in subjects with poorly
controlled diabetes. The authors concluded that the information obtained
from the CGMS was valuable and that it amounted to a significant
breakthrough in our ability to achieve optimal glycemic control.
Use of CGMS in pediatric subjects
The next paper was that of Gibson et al., entitled “Short-term Use of
the MiniMed Continuous Monitoring System to Determine Patterns of
Glycemia in Pediatric Patients with Type 1 Diabetes Mellitus”. The
authors stated that the purpose of their study was to determine if
glucose values obtained from the sensor provided more information than
that obtained from patient logbook records, particularly with regards to
the presence of nocturnal hypoglycemia, dawn phenomenon and hypoglycemia
unawareness and as to the effects of exercise, meals and insulin dosing
on glycemic profiles. The patient sample consisted of 47 pediatric
subjects who had a mean age of 11.8 ± 4.6 years and a mean diabetes
duration of 5.5 ± 3.5 years. The mean HbA1c was 8.6 ± 1.6% and the
mean number of days of sensor wear was 4 ± 1.
Study protocol
The following was done daily:
1. Four BG determinations
2. BG levels recorded in logbook and sensor
3. Coding of the following events in logbook and sensor: meals, meal
types, exercise, insulin doses, symptomatic hypoglycemia
4. Use of ExtendBar (a snack bar containing uncooked cornstarch).
The study aim was to find glycemic patterns from the logbook and sensor
data.
Results
As shown in Figure 2, more patterns were discerned with the sensor than
with the logbook.
There was a mean of 1.17 ± 1.3 episodes of nocturnal hypoglycemia per
patient per sensor wear. Nocturnal hypoglycemia was averted the nights
that subjects ingested ExtendBar (53% of subjects ingested ExtendBar).
The dawn phenomenon was seen in 16 patients (Table III).
Conclusion
The authors concluded that wearing the CGMS can provide important
information to health care providers and patients/families that could be
used to alter the diabetes regimen and improve glycemic outcome.
Summary
These two reports are beginning to reveal how the present CGMS might
benefit patients with Type 1 diabetes. Patterns and trends can be
identified so that alterations in the diabetes regimen can be made. If
done so correctly, HbA1c levels can be lowered. Of course, the device
described in these studies does not give the patients what they really
need – real-time data. Without real-time data, they cannot
continuously readjust their regimens, avert hypo- and hyperglycemia, and
deal effectively with alterations of the activity pattern and meal plan,
as they occur. However, until the real-time system is available, the
present form of CGMS appears to offer the patient and health care team
valuable information that can be used to improve outcomes – now.
