1. INTRODUCTION TO CONTINUOUS GLUCOSE MONITORS
H. Peter Chase, MD
Professor of Pediatrics
Barbara Davis Center
Aurora, CO
Keystone Conference
Wednesday, July 16, 2008
Barbara Davis Center for Childhood Diabetes May 2008

2. CGM Introduction Class
The slides from our course for families interested in starting CGM are available for use in your centers. They are on our website: The slides can then be accessed by any of the following methods:
1. Click on the “CGM Slideset” tab
2. In the “Online Books and Teaching Slides” page:
3. In the Clinical Resources section (last entry):

3. What is a CGM? (Continuous Glucose Monitor)
A device that provides “real-time” glucose readings and data about trends in glucose levels
Reads the glucose levels under the skin every 1-5 minutes (10-15 minute delay)
Provides alarms for high and low glucose levels and trend information
The 3rd era in diabetes management
Barbara Davis Center for Childhood Diabetes May 2008

4. Who Should Use a CGM?* The person and the family must both want a CGM
A youth must be willing to wear the sensor (and carry the receiver)
Using good diabetes care (4 BGs/day)
Good support system
Adequate body “real estate”
Cost of CGM (RNs to elaborate)
*(Understanding Pumps and CGMs, p.100)
Barbara Davis Center for Childhood Diabetes May 2008

5. Continuous Glucose Monitoring (CGM) WHY?
Prevention of low blood sugars (alarms)
Prevention of high blood sugars (ketones)
Minimize wide glucose fluctuations
Behavior Modification
Prevention of Complications (?)
Barbara Davis Center for Childhood Diabetes May 2008

6. How common are glucose levels <60mg/dl during the night in children with T1D?
French (i) and Australian (ii) data showed approximately 50% of children with low BG (<60mg/dl) during the night (on NPH bid)
DirecNet data (one night in hospital with blood sugars every 30 min.)
A) : 39 of 91 (43%) low BG
(44% of children on insulin pumps/56% on NPH)
B) 2004: 14 of 50 (28%) with low BG
(all on insulin pumps or Lantus)
Beregszaszi M, et al. J Pediatr. 131, 27, 1997
Porter PA, et al. J. Pediatr. 13, 366, 1997
Barbara Davis Center May 2008

7. Continuous Glucose Monitoring (CGM) WHY?
Prevention of low blood sugars (alarms)
Prevention of high blood sugars (ketones)
Minimize wide glucose fluctuations
Behavior Modification
Prevention of Complications (?)
Barbara Davis Center for Childhood Diabetes May 2008

8. “Snapshot of BG levels”
Barbara Davis Center for Childhood Diabetes May 2008

9. Continuous Glucose Monitoring
Barbara Davis Center for Childhood Diabetes May 2008

10. Hyperglycemia is common, especially after meals
50%
> 300
40%
30%
Breakfast
Lunch
20%
Dinner
10%
< 180 0%
Barbara Davis Center May 2008
Boland et al, Diabetes Care 24:1858, 2001

11. Continuous Glucose Monitoring (CGM) WHY?
Prevention of low blood sugars (alarms)
Prevention of high blood sugars (ketones)
Minimize wide glucose fluctuations
Behavior Modification
Prevention of Complications?
Barbara Davis Center for Childhood Diabetes May 2008

12. Three Parts to All CGMs:*
Sensor
Transmitter
Receiver/Monitor
*(Understanding Pumps and CGMs, p.103)
Barbara Davis Center for Childhood Diabetes May 2008

13. Sensor
(p.103)
Barbara Davis Center for Childhood Diabetes May 2008

14. B)Transmitter
(p.103)
Barbara Davis Center for Childhood Diabetes May 2008

15. C)Receiver or Monitor (p.103)
Barbara Davis Center for Childhood Diabetes May 2008

16. What does “Calibration” mean and why do I need to do it?
Calibration is a process that gives a fingerstick BG value to the CGM system so the values will align with each other
Number of Calibrations vary by device
Best times to calibrate are when the BG values are stable: before meals and before bed
Do not calibrate when arrows are present
Barbara Davis Center for Childhood Diabetes May 2008

17. What type of data will we get?
“Real-time” (Immediate)
i. Trend graphs (p.109)*
ii. Alarms (p.110)*
iii. Trend arrows (p.113)*
Barbara Davis Center May 2008
*(Understanding Pumps and CGMs)

18. i) TREND GRAPHS*
Trend graphs – Knowing a glucose level is 240 mg/dl may not be as important as knowing the “trend.”
*(Understanding Pumps and CGMs, p.103)
Barbara Davis Center for Childhood Diabetes May 2008

19. ii) ALARMS (p.109) Can warn patients of current or projected high and low blood sugar
Projected alarms: 10, 20, or 30 minute warning of impending hypo- or hyperglycemia (Navigator and Guardian devices)
Threshold alarms: warning when glucose is below or above a set value (all devices)
Barbara Davis Center for Childhood Diabetes May 2008

20. iii) TREND ARROWS (p.110) Rate of Change Arrows
Gives the up-to-the-minute glucose value and a rate of change arrow
Glucose rising quickly
>2 (mg/dL)/min
Glucose going up
1 to 2 (mg/dL)/min
Fairly stable glucose
-1 to 1 (mg/dL)/min
Glucose going down
-1 to -2 (mg/dL)/min
Glucose falling quickly
>-2 (mg/dL)/min
Barbara Davis Center for Childhood Diabetes May 2008

21. Second type of data: (Retrospective, must download)
Modal Day Graphs (p.113)
Pie Chart (p.114)
Statistics (p.113)
*(Understanding Pumps and CGMs, Chapter 17, p.109)
Barbara Davis Center for Childhood Diabetes May 2008

22. A) Case Study: Modal Day Graphs*
Teenager with T1D for 9.5 years
Started Navigator: Sept. 2005
Starting HbA1c: 7.1%
Most recent HbA1c: 6.0%
Current number of low BGs per week (<60 mg/dL or <3.3 mmol/L): 1/week
Three “modal-day” graphs:
*(Understanding Pumps and CGMs, p.113)
Barbara Davis Center for Childhood Diabetes May 2008

23. A) BASELINE GLUCOSE MODAL DAY: i) Prior to Navigator Use
Barbara Davis Center for Childhood Diabetes May 2008

24. A) GLUCOSE MODAL DAY Breakfast/Lunch Improvements ii) After three months of use
Barbara Davis Center for Childhood Diabetes May 2008

25. A) GLUCOSE MODAL DAY iii) Most recent report
Barbara Davis Center for Childhood Diabetes May 2008

26. B) PIE CHARTS (p.114)
Barbara Davis Center for Childhood Diabetes May 2008

27. C) STATISTICS (p.113)
Barbara Davis Center for Childhood Diabetes May 2008

28. (To “fine-tune” insulin and diabetes management)
USE OF CGM RESULTS:
(To “fine-tune” insulin and diabetes management)
Important not to overwhelm families
*** One change at a time ***
Look for patterns 2 out of 3 days
A behavior modification device  Missed boluses, snacking, low BGs on CGM
iv) Good initial communication with HCP
Barbara Davis Center for Childhood Diabetes May 2008

29. Questions? The presentation by the nurses will be next.
You will then examine the CGMs from 3 companies.
Barbara Davis Center for Childhood Diabetes May 2008

30. Part 2: CLINICAL STUDIES
Use of CGM (The Navigator) in Clinical Studies of Children:
A) Insulin Pump Study (JPediatr 151:388,2007)
B) Lantus Study (DiabetesCare 31:525,2008)

31. CGM can help with glycemic control
A) 30 Pump Patients Using Navigator x 13 weeks* N 30
Mean Age
T1D duration
11.2 yr
5.8 years
Female
40%
HbA1c
Initial wks
7.1±0.6% ±0.7%
(p=0.02)
*DirecNet J Pediatri 151,388,2007

32. * HbA1c HbA1c (%) § Baseline Week 7 Week 13 Week 26 Baseline A1c 7.0%
8.5
Baseline A1c 7.0%
Baseline A1c >7.0%
8.0
N=15
7.5 *
N=15
N=12
N=15
HbA1c (%)
7.0
N=13
6.5
N=15
N=15
N=13
6.0
5.5
Baseline
Week 7
Week 13
Week 26
Black dots denote mean values and boxes denote median, 25th and 75th percentiles.
* p=0.004 vs. baseline; § p=0.002 vs. wks 9-13.

33. Percentage of Navigator Glucose Values in Target Range
90%
Baseline A1c 7.0%
Baseline A1c >7.0%
80%
70%
N=11
N=13
N=15
Percent in target range (71-180)
60%
N=11
N=15
N=9
N=15
N=15
N=11
50%
N=14
40%
30%
Baseline
Wks
1-4
Wks 5-8
Wks 9-13
Wks 14-17
Wks 18-21
Wks 22-26

34. Percentage of Navigator Glucose Values
Below 70 mg/dL
14%
Baseline A1c 7.0%
12%
Baseline A1c >7.0%
10% 8%
Percent below 70 mg/dL
N=13
N=13
N=11
N=13 6%
N=15
N=15
N=11
N=11 4%
N=15
N=11
N=15
N=15 2%
N=14
N=9 0%
Baseline
Wks 1-4
Wks 5-8
Wks 9-13
Wks 14-17
Wks 18-21
Wks 22-26

35. B) Lantus Subjects using CGM*
27 (23 completed)
Age
11.0 ± 3.9 yr
Female
14 (52%)
Caucasian
25 (93%)
HbA1c
7.9 ± 1.0%
T1D duration
4.0 ± 3.1 yr
MDI Regimen
Glargine + RAIA*
Glargine + RAIA* + NPH
Other
21 (78%)
5 (16%)
1 ( 4%)
* DirecNet: Diabetes Care 31:525, 2008

36. Lantus Subjects using CGM Results – Glycemic Control
9.5
Baseline A1c > 7.5%
Baseline A1c ≤ 7.5%
9.0
8.5 *
8.0
HbA1c (%)
7.5 **
7.0
6.5
6.0
** p = 0.03
* p = 0.02
5.5
Baseline
Week 7
Week 13

37. Lantus Subjects using CGM Results – Glycemic Variability
180
Baseline A1c > 7.5%
Baseline A1c ≤ 7.5%
160 *
140
Mean Amplitude of Glycemic
Excursion (MAGE, mg/dL)
120 **
100
** p = 0.17
* p = 0.004 80
Baseline
Wks 1-4
Wks 5-8
Wks 9-13

38. Lantus Subjects using CGM Conclusions
Use of the Navigator CGM was associated with an improvement in glycemic control without an accompanying rise in hypoglycemia
Glycemic variability decreased with use of the Navigator
Subjects and parents reported high overall satisfaction with the Navigator and did not demonstrate deterioration in quality of life during 3-month use
CGM are tolerable and effective in children using MDI regimens

39. CGM Influences on Glucose Levels
Blinded vs Non-Blinded CGM Tracings:
p-value
21% less time <55 mg/dl <0.001
23% less time >240 mg/dl <0.001
26% more time in target <0.001
(81 – 140 mg/dl)
(Garg et al, Diabetes Care 27:1922,2004)

40. COMMON MISCONCEPTIONS OF CGM (QUIZ)
1) “If I use CGM, I do not have to do BG checks anymore.”
Barbara Davis Center for Childhood Diabetes May 2008

41. COMMON MISCONCEPTIONS OF CGM
2) “The starting of CGM will make diabetes management a breeze – so simple!”
Barbara Davis Center for Childhood Diabetes May 2008

42. COMMON MISCONCEPTIONS OF CGM
3) “The use of CGM will fix the diabetes – all blood sugars will be perfect.”
Barbara Davis Center for Childhood Diabetes May 2008

43. COMMON MISCONCEPTIONS OF CGM
4) “My CGM values should match my BG values.”
Barbara Davis Center for Childhood Diabetes May 2008

44. COMMON MISCONCEPTIONS OF CGM
5) “The alarms will catch every low or pending low so I don’t need to worry about lows anymore.”
Barbara Davis Center for Childhood Diabetes May 2008

45. CLOSED LOOP (BIONIC) PANCREAS
“The Future”
Will probably come in parts
JDRF supporting algorithm development
Should reduce glucose highs, lows, and fluctuations
Will probably be more realistic than islet cell transplant
FDA and medical insurance approvals (as with CGM) will be critical

46. Q. Why combine insulin pumps (CSII) and Continuous Glucose Monitors (CGM)? (p121)
A: “They complement each other tremendously and provide the most ‘state of the art’ diabetes care available.”
The CGM helps with:
Cannulas dislodging
Missed food boluses
Hypoglycemia
Corrections

47. Our Initial Data:
Two oral presentations at ADA in June, 2008 (Abstract # 230-OR and 42-OR).
Our emphasis: Preventing severe hypoglycemia at night.
This may be the first part of a closed loop system acceptable to the FDA.
We have shown that 80% of pending lows can be predicted.
Safety remains the primary goal.

48. “Now let me get this right, Dr. Chase… You want the elves to make an
artificial pancreas?”
THANK YOU