1 INTRODUCTION TO CONTINUOUS GLUCOSE MONITORS H. Peter Chase, MD Professor of Pediatrics Barbara Davis Center Aurora, CO Keystone Conference Wednesday,

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INTRODUCTION TO CONTINUOUS INTRODUCTION TO CONTINUOUS GLUCOSE MONITORSGLUCOSE MONITORS

H. Peter Chase, MDProfessor of Pediatrics

Barbara Davis Center

Aurora, CO

Keystone Conference

Wednesday, July 16, 2008

Barbara Davis Center for Childhood Diabetes May 2008

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CGM Introduction ClassCGM 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: www.barbaradaviscenter.org. 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:

http://www.uchsc.edu/misc/diabetes/books.html• 3. In the Clinical Resources section (last entry): http://www.uchsc.edu/misc/diabetes/school.html

http://www.barbaradaviscenter.org/

http://www.uchsc.edu/misc/diabetes/books.html

http://www.uchsc.edu/misc/diabetes/books.html

http://www.uchsc.edu/misc/diabetes/school.html

http://www.uchsc.edu/misc/diabetes/school.html

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What is a CGM?What is a CGM? (Continuous Glucose Monitor) (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


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Who Should Use a CGM?*Who Should Use a CGM?*

1) The person and the family must both want a CGM

2) A youth must be willing to wear the sensor (and carry the receiver)

3) Using good diabetes care (4 BGs/day)4) Good support system5) Adequate body “real estate”6) Cost of CGM (RNs to elaborate)

*(Understanding Pumps and CGMs, p.100)


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Continuous Glucose Monitoring (CGM) WHY?

A.Prevention of low blood sugars (alarms)

B. Prevention of high blood sugars (ketones)

C.Minimize wide glucose fluctuations

D.Behavior Modification

E. Prevention of Complications (?)


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How common are glucose levels <60mg/dl How common are glucose levels <60mg/dl during the night in children with T1D?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) 2001-2002: 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)

i) Beregszaszi M, et al. J Pediatr. 131, 27, 1997ii) Porter PA, et al. J. Pediatr. 13, 366, 1997Barbara Davis Center May 2008

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A. Prevention of low blood sugars (alarms)

B.Prevention of high blood sugars (ketones)



E. Prevention of Complications (?)


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“Snapshot of BG levels”


99

Continuous Glucose Monitoring


1010

Hyperglycemia is common, Hyperglycemia is common, especially after mealsespecially after meals

0%

10%

20%

30%

40%

50%

< 180 181 - 240 241 - 300 > 300

Breakfast

Lunch

Dinner

Boland et al, Diabetes Care 24:1858, 2001Barbara Davis Center May 2008

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A. Prevention of low blood sugars (alarms)

B. Prevention of high blood sugars (ketones)



E. Prevention of Complications?


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Three Parts to All CGMs:*Three Parts to All CGMs:*

A. Sensor

B. Transmitter

C. Receiver/Monitor*(Understanding Pumps and CGMs, p.103)


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A)Sensor (p.103)


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B)Transmitter(p.103)


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C)Receiver or Monitor(p.103)


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What does “Calibration” mean and What does “Calibration” mean and why do I need to do it?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 presentBarbara Davis Center for Childhood Diabetes May 2008

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What type of data will we get?

1) “Real-time” (Immediate)

i. Trend graphs (p.109)*

ii. Alarms (p.110)*

iii. Trend arrows (p.113)*

*(Understanding Pumps and CGMs)Barbara Davis Center May 2008

Trend graphs – Knowing a glucose level is 240 mg/dl may not be as important as knowing the “trend.”

i) TREND GRAPHS*



ii) ALARMS (p.109)ii) ALARMS (p.109) Can warn patients of current or Can warn patients of current or

projected high and low blood sugarprojected 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)


iii) TREND ARROWS (p.110)iii) TREND ARROWS (p.110)Rate of Change ArrowsRate of Change Arrows

Gives the up-to-the-minute glucose value and a rate of change arrow

Glucose going down-1 to -2 (mg/dL)/min

Glucose going up1 to 2 (mg/dL)/min

Glucose falling quickly>-2 (mg/dL)/min

Fairly stable glucose -1 to 1 (mg/dL)/min

Glucose rising quickly>2 (mg/dL)/min


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Second type of data:Second type of data:(Retrospective, must download)(Retrospective, must download)

2) Retrospective

A.Modal Day Graphs (p.113)

B.Pie Chart (p.114)

C.Statistics (p.113)*(Understanding Pumps and CGMs, Chapter 17, p.109)


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A) Case Study:A) Case Study:Modal Day Graphs*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:



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A) BASELINE GLUCOSE MODAL DAY:A) BASELINE GLUCOSE MODAL DAY:i) Prior to Navigator Usei) Prior to Navigator Use


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A) GLUCOSE MODAL DAYBreakfast/Lunch Improvements

ii) After three months of useii) After three months of use


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A) GLUCOSE MODAL DAYiii) Most recent reportiii) Most recent report


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B) PIE CHARTS (p.114)


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C) STATISTICS (p.113)


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USE OF CGM RESULTS:(To “fine-tune” insulin and diabetes management)

i) Important not to overwhelm families

*** One change at a time ***

ii) Look for patterns 2 out of 3 days

iii) A behavior modification device Missed boluses, snacking, low BGs on CGM

iv) Good initial communication with HCP


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Questions?Questions?

• The presentation by the nurses will be next.

• You will then examine the CGMs from 3 companies.


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Part 2: CLINICAL STUDIESPart 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)

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CGM can help with glycemic control

N 30

Mean Age

T1D duration

11.2 yr

5.8 years

Female 40%

HbA1c Initial 13 wks7.1±0.6% 6.8±0.7%

(p=0.02)

A) 30 Pump Patients Using Navigator x 13 weeks*

*DirecNet J Pediatri 151,388,2007

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HbA1cH

bA

1c (

%)

5.5

6.0

6.5

7.0

7.5

8.0

8.5

Baseline Week 7 Week 13 Week 26

Baseline A1c 7.0%Baseline A1c >7.0%

Black dots denote mean values and boxes denote median, 25 th and 75th percentiles.

N=15

N=15N=15

N=15

N=13

N=15

N=13

N=12

* p=0.004 vs. baseline; § p=0.002 vs. wks 9-13.

§

*

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Percentage of Navigator Glucose Valuesin Target Range

30%

40%

50%

60%

70%

80%

90%

Baseline Wks1-4

Wks5-8

Wks9-13

Wks14-17

Wks18-21

Wks22-26

Pe

rce

nt

in t

arg

et r

an

ge

(71

-1

80)


N=14

N=15 N=15N=15

N=11N=9

N=11

N=11

N=11 N=13

N=13 N=15

N=15N=13

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Percentage of Navigator Glucose Values Below 70 mg/dL

Per

cen

t b

elo

w 7

0 m

g/d

L

0%

2%

4%

6%

8%

10%

12%

14%

Baseline Wks1-4

Wks5-8

Wks9-13

Wks14-17

Wks18-21

Wks22-26


N=11

N=11

N=13N=13

N=15N=15

N=13

N=14

N=15N=15

N=15N=11

N=9

N=11

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N 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

B) Lantus Subjects using CGM*

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Lantus Subjects using CGMLantus Subjects using CGMResults – Glycemic ControlResults – Glycemic Control

Hb

A1c

(%

)

5.5

6.0

6.5

7.0

7.5

8.0

8.5

9.0

9.5

Baseline A1c ≤ 7.5%Baseline A1c > 7.5%

Baseline Week 7 Week 13

** p = 0.03* p = 0.02

*

**

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Lantus Subjects using CGMLantus Subjects using CGMResults – Glycemic VariabilityResults – Glycemic Variability

Mea

n A

mp

litu

de

of

Gly

cem

icE

xcu

rsio

n (

MA

GE

, m

g/d

L)

80

100

120

140

160

180

Baseline Wks 1-4 Wks 5-8 Wks 9-13

Baseline A1c ≤ 7.5%Baseline A1c > 7.5%

*

**

** p = 0.17 * p = 0.004

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• 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

Lantus Subjects using CGM Conclusions

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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)

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COMMON MISCONCEPTIONS OF CGM(QUIZ)

1) “If I use CGM, I do not have to do BG checks anymore.”


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2) “The starting of CGM will make diabetes management a breeze – so simple!”

COMMON MISCONCEPTIONS OF CGM


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3) “The use of CGM will fix the diabetes – all blood sugars will be perfect.”



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4) “My CGM values should match my BG values.”



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5) “The alarms will catch every low or pending low so I don’t need to worry about lows anymore.”



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CLOSED LOOP (BIONIC) PANCREAS

“The Future”

i) Will probably come in parts

ii) JDRF supporting algorithm development

iii) Should reduce glucose highs, lows, and fluctuations

iv) Will probably be more realistic than islet cell transplant

v) FDA and medical insurance approvals (as with CGM) will be critical

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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

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Our Initial Data:Our Initial Data:

1. Two oral presentations at ADA in June, 2008 (Abstract # 230-OR and 42-OR).

2. Our emphasis: Preventing severe hypoglycemia at night.

3. This may be the first part of a closed loop system acceptable to the FDA.

4. We have shown that 80% of pending lows can be predicted.

5. Safety remains the primary goal.

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“Now let me get this right, Dr. Chase… You want the elves to make an

artificial pancreas?”THANK YOU

Documents

1 INTRODUCTION TO CONTINUOUS GLUCOSE MONITORS H. Peter Chase, MD Professor of Pediatrics Barbara Davis Center Aurora, CO Keystone Conference Wednesday,