Practical Aspects of Practical Aspects of Continuous Continuous

Glucose MonitoringGlucose Monitoring20082008

Rosanna Fiallo-Scharer, MDRosanna Fiallo-Scharer, MDLaurel Messer, RN, BSN, CDELaurel Messer, RN, BSN, CDE

Barbara Davis Center for Childhood DiabetesBarbara Davis Center for Childhood Diabetes

Presentation OutlinePresentation Outline

Historical backgroundHistorical background

Accuracy & researchAccuracy & research

Insurance coverage for Insurance coverage for pediatricspediatrics

Barbara Davis Center Barbara Davis Center experienceexperience

Real-Time and retrospective Real-Time and retrospective use of CGM use of CGM

Practical child and family issuesPractical child and family issues

CGMCGM

Historical BackgroundHistorical Background

CGMSCGMS®® – FDA- approved in 1999FDA- approved in 1999– Retrospective review of downloaded dataRetrospective review of downloaded data– Principle: Glucose oxidase-coated subcutaneous Principle: Glucose oxidase-coated subcutaneous

sensorsensor

Glucowatch BiographerGlucowatch Biographer– FDA- approved in 2001FDA- approved in 2001– First approved real time device First approved real time device – Principle: reverse iontophoresis through intact skinPrinciple: reverse iontophoresis through intact skin

Real Time Continuous Glucose Real Time Continuous Glucose MonitoringMonitoring

Freestyle Navigator

Dexcom STS

Paradigm Real Time System

Continuous Glucose MonitorsThe DirecNet experience

Inpatient Accuracy StudyInpatient Accuracy Study

Principal Aim:Principal Aim:

To assess the accuracy of the To assess the accuracy of the Medtronic MiniMed CGMS and the Medtronic MiniMed CGMS and the GlucoWatch Biographer II vs. gold GlucoWatch Biographer II vs. gold standard plasma glucose standard plasma glucose measurements in children with T1DMmeasurements in children with T1DM

Subject DemographicsSubject Demographics

• 91 Children and 91 Children and AdolescentsAdolescents

• 51% Female51% Female• 43% Pumpers43% Pumpers• Mean HbA1c = 7.8Mean HbA1c = 7.8%%

Ages of Subjects

3 to < 7

7 to < 12

12 to < 18

Daily Glucose VariationsDaily Glucose Variations

40

60

80

100

120

140

160

180

200

220

240

260

280

300

320

340

360

380

400

2:00 PM 3:00 PM 4:00 PM 5:00 PM 6:00 PM 7:00 PM 8:00 PM 9:00 PM 10:00PM

11:00 PM 12:00AM

1:00 AM 2:00 AM 3:00 AM 4:00 AM 5:00 AM 6:00 AM 7:00 AM 8:00 AM 9:00 AM 10:00AM

11:00AM

12:00PM

1:00 PM 2:00 PM

gluc

ose

(mg/

dl)

Procedure•Regular meals and insulin doses•GS glucose q30-60 min

ResultsResultsnn r Mean RAD Median RAD Within r Mean RAD Median RAD Within

ISOISO

GWB GWB 3,6723,672 0.860.86 22% 22% 16%16% 80%80%

CGMS CGMS (original) (original) 5,6585,658 0.770.77 26% 26% 19%19% 53%53%

CGMS CGMS (Modified) (Modified) 1,120 1,120 0.90 0.90 16% 16% 11%11% 72% 72%

UltraUltra 2,0682,068 0.970.97 6% 6% 9%9% 94%94%

ISO Criteria: If reference glucose ≤ 75 mg/dL, sensor glucose within ± 15 mg/dL; if reference glucose > 75 mg/dL, sensor glucose within ± 20%.

Diabetes Technology &Therapeutics Vol 5 (5), 2003

Factors Factors NOTNOT Impacting Accuracy Impacting Accuracy For Either the GW or CGMSFor Either the GW or CGMS

Age of the SubjectAge of the Subject

BMI (body mass index)BMI (body mass index)

Sensor age (CGMS)Sensor age (CGMS)

Location of GWB placementLocation of GWB placement– Upper vs lower armUpper vs lower arm– Inner vs outer armInner vs outer arm

0%

5%

10%

15%

20%

25%

30%

35%

40%

0 50 100 150 200 250 300 350 400

Reference Glucose (mg/dL)

Median RAD

GWB

Original CGMS

Modified CGMS

Sensor Accuracy by Glucose LevelSensor Accuracy by Glucose Level

CGMS Sensitivity and False Alarm CGMS Sensitivity and False Alarm rate for detection of hypoglycemiarate for detection of hypoglycemia

Alarm Setting Alarm Setting SensitivitySensitivity False Alarm RateFalse Alarm Rate

(mg/dl)(mg/dl)

6060 49%49% 58%58%

8080 84%84% 64%64%

100 100 100%100% 75%75%

120 120 100%100% 84%84%

Down alertDown alert

Only 24% and 8% of truly hypoglycemic Only 24% and 8% of truly hypoglycemic incidents were detected by the simple incidents were detected by the simple alarm during the hypoglycemia test and alarm during the hypoglycemia test and overnight, respectively overnight, respectively

Combining the simple alarm with the down Combining the simple alarm with the down alert improves those sensitivity rates to alert improves those sensitivity rates to 88% and 77%, respectively 88% and 77%, respectively

Diabetes Technol Ther. 2004 Oct; 6(5): 559-66

Accuracy of the Freestyle Navigator Accuracy of the Freestyle Navigator and Guardian RTand Guardian RT

Diabetes Care. 2007 Jan; 30 (1):59-64

ResultsResultsnn Median RAD Median RAD Within ISO Within ISO

Guardian RTGuardian RT 1,4341,434 14% 14% 64% 64%

Navigator Navigator 1,8111,811 12% 12% 74%74%

UltraUltra 2,068 2,068 9% 9% 94%94%

ISO Criteria: If reference glucose ≤ 75 mg/dL, sensor glucose within ± 15 mg/dL;

if reference glucose > 75 mg/dL, sensor glucose within ± 20%.

These devices have sufficient accuracy to These devices have sufficient accuracy to allow tracking of glucose valuesallow tracking of glucose values

However, neither device is as accurate as However, neither device is as accurate as meters presently available on the marketmeters presently available on the market

Particularly useful for detecting post-Particularly useful for detecting post-prandial glycemic excursions and prandial glycemic excursions and overnight glucose trendsovernight glucose trends

ConclusionsConclusions

GWB2 Randomized Controlled GWB2 Randomized Controlled TrialTrial

Diabetes Care. 2005 May; 28(5):1101-6

HbA1cHbA1c

Ultra Daily UseUltra Daily Use

First Month:First Month: 5.1 5.1 ± 1.6 in Usual ± 1.6 in Usual Care group, 5.6Care group, 5.6 ± 1.7 in GWB group± 1.7 in GWB group

Third Month:Third Month: 5.1 ± 1.8 in Usual Care 5.1 ± 1.8 in Usual Care group, 5.3 ± 1.6 in GWB groupgroup, 5.3 ± 1.6 in GWB group

Sixth Month:Sixth Month: 4.8 ± 1.7 in Usual Care 4.8 ± 1.7 in Usual Care group, 5.1 ± 1.7 in GWB groupgroup, 5.1 ± 1.7 in GWB group

GW2B useGW2B use

First Month:First Month: 2.1 2.1 ± 0.8 uses per week ± 0.8 uses per week (64% = at least 2 sensors/ week)(64% = at least 2 sensors/ week)Third Month:Third Month: 1.6 ± 0.7 uses per week (7 of the 99 subjects discontinued 1.6 ± 0.7 uses per week (7 of the 99 subjects discontinued GW2B use)GW2B use)

Sixth Month:Sixth Month: 1.5 ± 0.6 uses per week (26 of the 98 subjects discontinued 1.5 ± 0.6 uses per week (26 of the 98 subjects discontinued GW2B use)GW2B use)Questionnaire regarding non-use of the GW2B (55 subjects)Questionnaire regarding non-use of the GW2B (55 subjects)

76% = “skin irritation”76% = “skin irritation”56% = “skips too frequently”56% = “skips too frequently”47% = “alarms too frequently”47% = “alarms too frequently”33% = “readings not accurate”33% = “readings not accurate”31% = “too busy to use it”31% = “too busy to use it”22% = “forget to use it”22% = “forget to use it”

18% = “did not help with diabetes18% = “did not help with diabetes management” management”

Lesson learned:Lesson learned:

For CGM to help with diabetes For CGM to help with diabetes management, patients must use management, patients must use them!them!

Freestyle Navigator Pilot trialFreestyle Navigator Pilot trial

Journal Pediatr. 2007 Oct; 151 (4): 388-93

SummarySummary

57 pediatric subjects enrolled57 pediatric subjects enrolled– 30 Pumpers30 Pumpers– 27 MDI27 MDI

A1c data collected at 13 weeksA1c data collected at 13 weeks

Voluntary sensor use offered after 13 weeksVoluntary sensor use offered after 13 weeks

73% of pump users continued to use sensor at 73% of pump users continued to use sensor at 12 months and 78% of MDI users continued at 12 months and 78% of MDI users continued at 10 months (median hrs/wk 98 and 85 10 months (median hrs/wk 98 and 85 respectively)respectively)

A Randomized Clinical Trial to A Randomized Clinical Trial to Assess the Efficacy of Real-Assess the Efficacy of Real-Time Continuous Glucose Time Continuous Glucose

Monitoring in the Management Monitoring in the Management of Type 1 Diabetesof Type 1 Diabetes

funded by a grant from funded by a grant from the Juvenile Diabetes Research the Juvenile Diabetes Research

FoundationFoundation

Clinical Trial DesignClinical Trial Design

450 subjects age >=8 years• 330 with A1c >7.0% and 120 with HbA1c <7.0%• 1/3 in each age group: 8-<15, 15-<25, >25• 50% pump users, 50% MDI

Randomization to RT-CGM or Usual Care• Navigator, DexCom, Paradigm/Guardian REAL-Time

Primary outcome at 6 months

Months 7-12: both groups use RT-CGM

Outcomes: HbA1c, hypoglycemia, quality of life

Cost-effectiveness ancillary study

Current statusCurrent statusJDRF RCTJDRF RCT

6 month data collection already completed6 month data collection already completed

12 month data collection still in progress.12 month data collection still in progress.

Insurance coverage for Insurance coverage for pediatricspediatrics

Currently only one device approved for Currently only one device approved for pediatric usepediatric use

Real time technology not universally Real time technology not universally coveredcovered

Some success with approval on case by Some success with approval on case by case basiscase basis

Usually approved on appeals processUsually approved on appeals process

Presentation OutlinePresentation Outline

RT- CGM systems for pediatricsRT- CGM systems for pediatrics

Accuracy & researchAccuracy & research

Insurance coverage for pediatricsInsurance coverage for pediatrics

Barbara Davis Center experienceBarbara Davis Center experience

Real-Time and retrospective use Real-Time and retrospective use of CGMof CGM

Practical child and family issuesPractical child and family issues

Barbara Davis CenterBarbara Davis Centerexperience with CGMexperience with CGM

Currently: 100+ pediatric pts on CGMCurrently: 100+ pediatric pts on CGM

5 years old through adulthood5 years old through adulthood

Commercially: Paradigm REAL-Time, Dexcom Commercially: Paradigm REAL-Time, Dexcom SEVENSEVEN

Research: NavigatorResearch: Navigator

Varied experiences with devicesVaried experiences with devices

Using a sensor on daily basisUsing a sensor on daily basis

Insert sensor (every 3-7 days)Insert sensor (every 3-7 days)Warm up period with no glucose readingsWarm up period with no glucose readingsEntering fingerstick BG for calibrationsEntering fingerstick BG for calibrationsDevice starts reading REAL-TIME Device starts reading REAL-TIME informationinformationOccasional downloading Occasional downloading of device for of device for RETROSPECTIVE RETROSPECTIVE informationinformation

Real Time CGM UseReal Time CGM Use

SENSOR glucose levels SENSOR glucose levels Different from BG levels due to lag timeDifferent from BG levels due to lag time

Updates every 1-5 minutesUpdates every 1-5 minutes

ArrowsArrows

AlarmsAlarms

Trend informationTrend information

Real Time CGM UseReal Time CGM Use

EDUCATION POINT:EDUCATION POINT:– Must always do a BG for insulin, Must always do a BG for insulin,

treatment and management decisionstreatment and management decisions

WHY?

• No device currently FDA approved for replacement therapy

• Sensor may not be reading accurately

Retrospective dataRetrospective dataDownloaded at home or in clinicDownloaded at home or in clinic

(anyone have experience with this?)(anyone have experience with this?)

Retrospective dataRetrospective dataEDUCATION POINTSEDUCATION POINTS

Must know the WHY before knowing WHAT Must know the WHY before knowing WHAT to change!to change!

Make dosing changes if BG/SG is out of Make dosing changes if BG/SG is out of range range 2 out of 3 days2 out of 3 days

Important to look at trendsImportant to look at trendsLook at most recent weekLook at most recent week

Questions before changing: missed bolus? Questions before changing: missed bolus? menses? Illness? Bad pump set? Mistake in dose? menses? Illness? Bad pump set? Mistake in dose? Sports?Sports?

Retrospective dataRetrospective data

Trend graphTrend graph

(sensor daily overlay, modal day)(sensor daily overlay, modal day)

Coming soon: JDRF online CGM Coming soon: JDRF online CGM school!school!

Pediatric issuesPediatric issues

ExpectationsExpectations

Sensor stickingSensor sticking

SportsSports

AlarmsAlarms

CalibrationsCalibrations

Family dynamicsFamily dynamics

Pediatric issuesPediatric issues

ExpectationsExpectations

ExpectationsExpectationsNo fingerstick BGsNo fingerstick BGsWill read from the moment you put onWill read from the moment you put onAlarms will prevent all highs and lowsAlarms will prevent all highs and lows

Reality:Reality:4-8 BGs per day4-8 BGs per dayPeriods where not calibrated, not readingPeriods where not calibrated, not readingSensor errors for no reasonSensor errors for no reasonAlarms annoyingAlarms annoying

Pediatric issuesPediatric issues

Sensor stickingSensor stickingThree main problems:Three main problems:

1) Sensor does not stick1) Sensor does not stickTry different types of preps (IV prep, skin prep, Skin Try different types of preps (IV prep, skin prep, Skin Tac, Mastisol, tincture of benzoine Tac, Mastisol, tincture of benzoine

2) Tape or preps causes skin reactions2) Tape or preps causes skin reactionsTry different preps or tapesTry different preps or tapesUse IV3000/Tegaderm FIRST, and cut hole for Use IV3000/Tegaderm FIRST, and cut hole for sensor to insert throughsensor to insert through

3) Not enough skin “real estate” 3) Not enough skin “real estate” Try different sensorsTry different sensorsPinch up even if not indicated Pinch up even if not indicated

Chart on handoutChart on handout

Pediatric issuesPediatric issues

Sensor sticking Sensor sticking

PlacementPlacementConsider where least impact and movementConsider where least impact and movement

Arm– can cover with ace bandage for extra Arm– can cover with ace bandage for extra support (take off at night)support (take off at night)

SweatingSweatingUse antiperspirant under tapeUse antiperspirant under tape

BreakingBreakingNever take CGM receiver out into gameNever take CGM receiver out into game

Pediatric issuesPediatric issues

SportsSportsPROBLEM: CGM sensors fall off, sweat off, get broken

Calibration reminder * Calibration Calibration reminder * Calibration error * Replace sensor * High error * Replace sensor * High Glucose * Low Glucose * Projected Glucose * Low Glucose * Projected Low Glucose * Projected High Low Glucose * Projected High Glucose * Meter BG Now * Sensor Glucose * Meter BG Now * Sensor end * Wend * Weak signal * Disconnected * Low transmitter * Bad transmitter * Sensor error * Bad sensor

Pediatric issuesPediatric issues

AlarmsAlarmsPROBLEM: Alarms can become Alarms can become overwhelming/ annoying Why?.... overwhelming/ annoying Why?....

HIGH ALARM: 250-300 mg/dl*HIGH ALARM: 250-300 mg/dl*

LOW ALARM: 70-80 mg/dlLOW ALARM: 70-80 mg/dlConsider higher with hypoglycemia unawarenessConsider higher with hypoglycemia unawareness

Can gradually “tighten” alarms as glucose levels get Can gradually “tighten” alarms as glucose levels get tightertighter

**My opinion only!My opinion only!

Pediatric issuesPediatric issues

AlarmsAlarms

GOAL: Set alarms that are GOAL: Set alarms that are MEANINGFUL and will NOT drive the MEANINGFUL and will NOT drive the

child crazy!child crazy!

Can I change the type of alarm notice?”Navigator:

YES: vibrate or sound at three different volumes

Medtronic: YES: vibrate or sound at different volumes

Dexcom: NO: Will first vibrate then sound at increasing volumes

Pediatric issuesPediatric issues

AlarmsAlarms

Solution: Improvise!Solution: Improvise!On bedside table (in a glass) or under pillow on On bedside table (in a glass) or under pillow on vibratevibrate

In hallway outside of roomIn hallway outside of room

Baby monitor Baby monitor

Sibling in the room!Sibling in the room!

Spy equipmentSpy equipment

Paradigm Real-Time: More difficult because Paradigm Real-Time: More difficult because usually under blankets– new tech coming soon!usually under blankets– new tech coming soon!

Pediatric issuesPediatric issues

Overnight alarmsOvernight alarms

PROBLEM: Parent/child has difficulty hearing Parent/child has difficulty hearing alarms at nightalarms at night

Pediatric issuesPediatric issues

CalibrationsCalibrations

GOAL: Be the BOSS of the Calibration: Only GOAL: Be the BOSS of the Calibration: Only enter a calibration if BGs are STABLEenter a calibration if BGs are STABLE

SOLUTION: Calibrate before meals or 2 hours SOLUTION: Calibrate before meals or 2 hours after food or insulin shotafter food or insulin shot– Less likely to get a failed calibration alarmLess likely to get a failed calibration alarm– More likely to get accurate sensor readingsMore likely to get accurate sensor readings

PROBLEM: Calibration alarms annoying, Calibration alarms annoying, inconvenient, and when fail, are frequentinconvenient, and when fail, are frequent

Family issues and dynamicsFamily issues and dynamics

Adaptation: “It is just part of our life now. I wear it all the Adaptation: “It is just part of our life now. I wear it all the time and don’t think much about it anymore.” 12 y.o. time and don’t think much about it anymore.” 12 y.o. femalefemale

Anxiety: “ I was worried that my mom was mad at my blood Anxiety: “ I was worried that my mom was mad at my blood sugars all the time so I didn’t want to show her” 11 y.o. sugars all the time so I didn’t want to show her” 11 y.o. malemale

Ambivalence: “I like it when it works but I worry it is going to Ambivalence: “I like it when it works but I worry it is going to fall out and I will have to put a new sensor in again”fall out and I will have to put a new sensor in again”

14 y.o. male14 y.o. male

Family issues and dynamicsFamily issues and dynamics

THE BOTTOM LINE: THE BOTTOM LINE: They have to live They have to live with diabetes, not with CGMwith diabetes, not with CGM

Interval wear (example: 1 Interval wear (example: 1 sensor/week)sensor/week)

Occasional wear (example: during Occasional wear (example: during finals)finals)

Try again laterTry again later

The future of CGMThe future of CGM

SmallerSmaller

Longer sensor wearsLonger sensor wears

Less calibrationsLess calibrations

More insurance coverageMore insurance coverage

Closed loop system (insulin pump Closed loop system (insulin pump responds to sensor glucose levels)responds to sensor glucose levels)

Implantable sensorsImplantable sensors

Questions?Questions?