Making The Most
of Continuous Glucose
Monitoring
Gary Scheiner MS, CDE
Owner/Director, Integrated Diabetes Services
333 E. Lancaster Ave., Suite 204
Wynnewood, PA 19096
(877) 735-3648
www.integrateddiabetes.com
Gary@integrateddiabetes.com
Making the Most
of Continuous Glucose Monitoring
1. What Information Is Available?
2. How to Use Immediate Data?
3. How to Use Intermediate Data?
4. What Can Be Learned from
Retrospective Analysis?
5. Optimizing CGM System Performance
MiniMed Paradigm® &
Guardian® REAL-Time CGM Systems
On-Screen Reports
•
•
•
•
•
•
3-hr and 24-hr graphs (pump);
3 / 6 / 12 / 24-hr graphs
(Guardian)
Can scroll back for specific
data points
 “direction” indicators
Updates every 5 minutes
Hi/Low Alerts
Predictive Alerts (Guardian)
MiniMed Paradigm® &
Guardian® REAL-Time CGM Systems
CareLink™ Personal:
Online Reports
• Sensor
daily
overlay
• Sensor
overlay
by meal
MiniMed Paradigm® &
Guardian® REAL-Time CGM Systems
CareLink™ Personal
Online Reports
Daily summaries &
layered reports,
including…
•
Sensor tracing
•
Basal & bolus
delivery
•
Carbohydrate &
logbook entries
DexCom™ Seven Plus®
On-Screen Reports
• 1, 3, 6, 12, 24-hr
graphs
• Updates every 5
minutes
• Hi/Low alerts
• Rate of Change
alerts
DexCom™ 7 STS®
Dexcom DM2
Download Reports
Hourly Stats
Glucose Trend
DexCom™ 7 STS®
Dexcom DM2
Download Reports
Trend Analysis
BG
Distribution
Freestyle Navigator™
On-Screen Reports
•
•
•
•
2/4/6/12/24-hr line graphs
Predictive alerts
 “direction” indicators
Can scroll back to data points
•
Customizable time range:
• Highest, Lowest, Avg, SD
• % Time High, Low, In-Range
• # Hypo, Hyper events
•
Updates every minute
Freestyle Navigator™
Download to CoPilot Software
Modal Day Report
Glucose Line Report
Statistics Report
Practical Benefits of Real-Time CGM
• Rumble strips (avoid serious extremes)
• Peace of mind
• Basal & bolus fine tuning
• Postprandial analysis
• Insulin action curve determination
• Short-term Forecasting
• Learning tool & immediate feedback
• Eliminates some blood glucose checks???
Partially derived from: Hirsch, et al. Clinical Application of Emerging Sensor Technologies in Diabetes
Management: Consensus Guidelines for Continuous Glucose Monitoring (CGM). Diabetes Technology
& Therapeutics, 10:4, 2008, 232-244.
How to Look at the Information
• Immediate
• Intermediate
• Retrospective
Immediate Info: Alerts
• Customizable settings
• Vibrate and/or beep
• Alert the user of glucose levels that
have crossed specified high or low
thresholds
• (predictive) Alert of anticipated crossing
of high or low thresholds
Setting Alerts
• Hi/Low alarm thresholds are not BG
target ranges
• Balance need for alerts against “nuisance
factor”
Initial Alert Settings
Recommendation
LOW:
80 mg/dl (4.5 mmol)
90 (5) + if hypo unaware
HIGH:
300 mg/dl (16 mmol)
lower progressively toward 180 (10)
NOT RECOMMENDED: Low 70 (3.9)
NOT RECOMMENDED: High 140 (7.8)
Derived from: Hirsch, et al. Clinical Application of Emerging Sensor Technologies in Diabetes
Management: Consensus Guidelines for Continuous Glucose Monitoring (CGM). Diabetes Technology
& Therapeutics, 10:4, 2008, 232-244.
Special Alert Settings
• Young children (higher, wider range)
• Hypoglycemia unawareness, highrisk professions (higher hypo setting)
• Pregnancy (lower, narrower range)
• HbA1c of 11.0% (higher initially)
Immediate Info:
Glucose and Trend
• Prediction/Forecasting
• Safety/Performance
• Driving
• Sports
• Tests
Immediate Glucose Info:
Can it Replace
Fingersticks?
• Not during first 1-2 cycles of
using the system
• Wait at least 12 hrs after
sensor replacement
• If BG Stable
• If Recent calibrations in-line
• If No recent alarms
Immediate Info:
Potential Bolus Adjustment
Based on BG Direction
• BG Stable:
Usual Bolus Dose
• BG Rising Gradually:
 bolus 10%
• BG Rising Sharply:
 bolus 20%
• BG Dropping Gradually:
 bolus 10%
• BG Dropping Sharply:
 bolus 20%
Immediate Info:
Hypoglycemia Alerts
• Predictive Hypo Alert or
Hypo Alert & recovering:
Subtle Treatment
• 50% of usual carbs
• Med-High G.I. food
• Hypo Alert & Dropping:
Aggressive Treatment
• Full or increased carbs
• High G.I. food
Intermediate Info:
Use of 2/3/4 Hr Trend Graphs
• Effects of different food types
• Effectiveness of bolus amt.
• Reveals postprandial spikes
• Pramlintide/Exenatide Influence
• Exercise effects
• Impact of Stress
Intermediate Info:
Use of 9 / 12 / 24 Hr Trend Graphs
• Facilitates decision-making for basal
insulin doses
• Shows delayed effects of exercise,
stress, high-fat foods
• Reveals overnight patterns
• Lets user know when bolus action is
complete
Specific Insights to Derive
(a purely retrospective journey)
Before You Analyze, Qualify.
• Were sufficient calibrations performed?
• Did the calibrations match the CGM data
reasonably well?
• Was the data mostly continuous?
• Was the time/date set correctly?
These Are a Few
of My Favorite
Stats…
 Mean (avg) glucose
 % Of Time Above, Below, Within Target
Range
 Standard Deviation
 # Of High & Low Excursions Per Week
Case Study 1:
Effectiveness of Current Program
•
•
Type 1 diabetes; using insulin glargine & MDI
Overnight readings are OK; HbA1c levels are elevated
Glucose (mg/dL)
400
300
200
100
0
3 AM
6 AM
9 AM
12 PM
3 PM
6 PM
9 PM
Meal doses insufficient; not covering snacks?
Glucose (mg/dL)
Case Study 2a:
Basal Insulin Regulation
400
400
300
300
200
200
100
100
0
0
3 AM
9 AM
3 PM
9 PM
• Stable 12 AM – 4 AM, then
dropping pre-dawn
• Dropping late afternoon
3 AM
9 AM
3 PM
9 PM
• Rising 2 AM – 8 AM
Case Study 2b:
Basal Insulin Regulation
Type 1 diabetes; using insulin glargine & MDI
History of morning lows
Now not “covering” highs at night
400
Glucose (mg/dL)
•
•
•
300
200
100
0
3 AM
6 AM
9 AM
12 PM
3 PM
6 PM
9 PM
BG dropping overnight; insulin dose too high
Case Study 3:
Detection of Silent Hypoglycemia
•
Type1 diabetes; on pump
•
Frequent fasting highs (9 AM)
Glucose (mg/dL)
400
300
200
100
0
3 AM
6 AM
9 AM
12 PM
3 PM
6 PM
Somogyi effect during the night
9 PM
Case Study 4:
Determination of Insulin Action Curve
3-Hour
Duration
4-Hour
Duration
5-Hour
Duration
Case Study 5:
Fine-Tuning Meal Boluses
Glucose (mg/dL)
400
300
200
100
0
3 AM
Breakfast and
lunch doses
may be too low
6 AM
9 AM
12 PM
3 PM
Dinner dose
appears OK
6 PM
9 PM
Night-snack
dose clearly
insufficient
Case Study 6:
Fine-Tuning Correction Boluses
•
Dropping low after correcting for highs at bedtime
and wake-up time
400
Glucose (mg/dL)
300
200
100
0
3 AM
6 AM
9 AM
12 PM
3 PM
6 PM
9 PM
Need to change correction factor & insulin
sensitivity during AM hours
Case Study 7:
Postprandial Analysis
•
•
•
Pre-meal BG levels are usually in target range
HbA1c are higher than expected based on SMBG
Tired and lethargic after meals
Glucose (mg/dL)
400
300
Meal
200
100
Meal
Meal
Meal
Significant postprandial spikes (300s)
Case Study 8:
Impact of Physical Activity
•
•
•
Type 1 diabetes; pump user
Basal rates confirmed overnight
Exercises in the evening (9 PM)
400
Glucose (mg/dL)
Exercise
300
200
100
0
3 PM
6 PM
9 PM
12 AM
3 AM
6 AM
9 AM
Experiencing delayed-onset hypoglycemia
12 PM
Case Study 9:
Impact of Stress
•
•
Type 1 diabetes;
pump user
40 years old;
athletic
Handsome,
excellent speaker
•
Late for meeting
•
Gets flat tire; eats
15g carbs to prepare
for tire change
•
Spare is flat too!!
400
300
Glucose (mg/dL)
•
200
100
0
9 AM 12 PM 3 PM 6 PM
9 PM
STRESS CAN RAISE BLOOD GLUCOSE… A LOT!!!
Case Study 10:
Impact of Various Food Types
Pasta Meal
Stir-Fry Over Rice
BG peaks later with
pasta than rice
Cereal
Oatmeal
Yogurt
Postprandial peak:
cereal > oatmeal > yogurt
Case Study 11:
Impact of Hi-Fat Meals
Saturday Nights,
Dinner Out
Temp basal increase following hi-fat meals
CGM “Homework”
Assignments
 Verify basal doses
 See effect of dietary fat
 Study effects of specific exercises
 Evaluate impact of different food types
 Measure insulin sensitivity
 Determine insulin action curve
Download (if poss.) prior to appointments!
Optimizing CGM
System Performance
• Calibration
• Site selection/care
• Signal reception
• Ingredients for success
Optimal Calibration
• Calibrate at times when blood glucose
(BG) is stable (fasting, pre-meals)*
• Avoid calibrations during times of rapid
glucose change*
– Post meal
– UP or DOWN arrows are displayed
– In the period following a correction with food or
insulin
– During exercise
* Not required w/Dexcom system
Optimal Calibration
• Calibrate before bedtime to avoid alarms
during the night
• Use good technique when performing
BG checks for calibration
– Proper coding
– Clean hands
• USE FINGERSTICKS
• Enter the calibration immediately after
the fingerstick (Dexcom, Medtronic systems)
Sensor Sites
• Site Selection
– “Fleshy” areas
– At least 3” Away from insulin infusion
– Avoid tight clothing areas, scars, bruises, lipoatrophy
– Rotate sites
• Bleeding/Irritation
– Slight bleeding OK
– Profuse bleeding: remove
– Remove introducer needle at proper angle
Sensor Sites
• Adhesive
– Completely cover the Transmitter & Sensor
(Navigator & Medtronic systems)
– Check sensor daily for loose tape
– Apply extra tape over sensor & transmitter if tape
patch begins to “curl” around edges
• Site Irritation
– Watch for redness, swelling, tenderness
– Remove sensor with prolonged irritation (>1 hour)
Signal Reception
• Heed transmitter ranges
– Medtronic: 6 ft.
– Dexcom: 5 ft.
– Navigator: 10 ft.
• Signals do not travel well through water
– Wear receiver on same side of body as sensor
• Keep receiver very close while charging
(Dexcom)
• Charge transmitter fully every 6 days
(Medtronic)
Ingredients For Success
• Have the right expectations
• Wear the CGM at least 90% of the time
• Look at the monitor 10-20 times per day
• Do not over-react to the data; take IOB into
account
• Adjust your therapy based on trends/patterns
• Calibrate appropriately
• Minimize “nuisance” alarms
Think Like A Pancreas!