Transcript Current And Emerging Technologies In Insulin Pumps & Continuous Monitors May 8, 2008 John Walsh, PA, CDE [email protected] (619) 497-0900 Advanced Metabolic Care + Research 700 West.

Current And Emerging Technologies In
Insulin Pumps & Continuous Monitors
May 8, 2008
John Walsh, PA, CDE
[email protected]
(619) 497-0900
Advanced Metabolic Care + Research
700 West El Norte Pkwy
Escondido, CA 92126
(760) 743-1431
Highlights
 Background
 Smart Pumps and Features
 Pump Control Tips
 DIA and BOB
 Super Bolus
 Continuous Monitors and Tips
 Wrap Up
EDIC Study Findings
Lower Glucose Prevents Heart Attacks & Early Death

After the DCCT ended in 1993, the EDIC Study has
followed these participants.

Over 11 years, A1c levels in intensive and
conventional control groups have been identical at
7.9% (was ~7.4% and ~9.1%).

However, heart attacks and strokes have been twice
as high (98 vs 46) in the original conventional versus
intensive group, even though A1c levels have been
identical since the DCCT trial ended.
1. EDIC Study Group presentation at 2005 ADA, K.M. Venkat Narayan: Clinical Diabetes 24:88-89, 2006
EDIC Study Findings
Lower Glucose Temporarily Reduces Nerve Damage

The tight control group also
experienced half as much neuropathy

BUT, as shown in figure, improved
control in the past delays progression
but offers no long-term protection

Also, an A1c of 7.9% does not stop
progression of nerve damage
(or CVD)
Avg A1c = 7.9%
Take Home: Improve control and KEEP it there!
Diabetes Care, Vol 29, No. 2, pp. 340-344
Goal: A Healthy, Saner Life With Less
Glucose Exposure And Variability
The DCCT proved that exposure to high blood glucose was
damaging. New emphasis is on glucose variability.
400
380
360
Glucose Variability (Swing) =
340
320
SD* from PC or meter
300
glucose (mg/dl)
280
260
Glucose Exposure =
240
220
200
A1c or average BG from meter
180
160
140
120
100
80
60
40
2:00 PM 3:00 PM 4:00 PM 5:00 PM 6:00 PM 7:00 PM 8:00 PM 9:00 PM
10:00
PM
11:00 PM
12:00
AM
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
10:00
AM
11:00
AM
12:00
PM
1:00 PM 2:00 PM
Current Pump Reality
Pumps provide only modest improvements in
A1c levels over MDI:
 About 0.6% lower (mid to upper 8% range)
 Avg. A1c of 8.5% is well above goal of less
than 7% or 6.5%
But glucose levels ARE more stable with less
insulin needed per day
Smart Pump Features
Smart Pump Features – Overview
 Automatic carb and correction
calculations based on:
 Carb and correction factors
 Glucose targets
 DIA avoids insulin stacking
 Carb and correction boluses
adjusted for BOB for accuracy and safety
 Personal carb database
 Correction bolus shown as % of TDD
 Direct glucose entry and detailed glucose history
 Reminders, alerts, weekly schedule, temp basal rates, etc.
Deltec Cozmo
Features:
# Pumps
 HypoManager
1
 Weekly Schedule
1
 Missed Meal Bolus
1
 Bolus Not Completed
1
 Disconnect Bolus
1
 Basal Test
1
 Meal Maker with CozFoods 4
 Therapy Effectiveness
2
 BG Variability (SD)
1
Meter/CGM Improve BG History
•
•
Pump + Meter – direct BG entry
•
Deltec Cozmo + Freestyle CoZmonitor
•
Omnipod + Freestyle
•
Paradigm + Lifescan (US)/Bayer (Eur)
Pump + Cont Mon – no direct BG entry
•
•
Medtronic x22 + Paradigm RT
Future Pump + Meter/Monitor Combos
•
Animas pump + Lifescan meter
•
Cozmo + Abbott Navigator
•
Animas & Omnipod + Dexcom
•
AccuChek pump + meter
Disconnect Bolus
 Disconnect up to 2 hrs for
sports, sauna, sex, etc.
 Useful for “Mini-vacations”
 User estimates time off and
pump gives up to 50% of
missed basal as bolus
 Alarm reminds user to re-connect
 On reconnecting, pump shows missed basal and
offers to supply the missing amount
Weekly Schedule
 User’s profile changes automatically for specific
days of the week
 Allows different basal patterns and missed meal
bolus alerts for each day of the week
 No need to remember to change basal patterns or
alerts
 Great for college, shift work, weekends, exercise,
or other regular variation in schedule
Pump As Carb Counter
 Pump or external controller
contains user-selected food
list for accurate carb
counting for
 Easy carb calculations
 More accurate boluses
 Available in Animas 2020,
Deltec Cozmo, Omnipod
PDM, and Spirit PDA
Carb Bolus Varieties
Regular
 Taken immediately – for most meals
Extended / square wave
 Extended over time – gastroparesis
Combo / dual wave
 Some now, some later – bean burrito,
some pastas and pizzas, Symlin
Helpful Aids And Alerts
 Carb or insulin recommendation
for each BG
 Bolus-not-completed alert
 Missed meal bolus alert
 Check after high or low BG
 10 extra units for basal when reservoir reads zero
 Easier analysis with TDD and basal/bolus balance
 Overview of basal/bolus balance and correction bolus
Not available in all pumps
Getting The Big Picture
Therapy Effectiveness – A summary
of glucose and insulin history
Therapy Effectiveness Scorecard
 Screen 1:
 Average BG (over 2 to 30 days)
 BG tests per day
 BG standard deviation (SD)
 Screen 2:
 Carbs per day
 TDD
 % correction boluses
 % carb boluses
 % basal rates
Largely available in Paradigm pumps as well
Therapy Scorecard Screen 1
Monitor control, testing frequency, glucose variability
14 Day Average:
BG
146 mg/dl
Tests
3.5/day
Std Dev 53 mg/dl
Overall control
Adequacy of testing
BG variability – aim for
less than 65 mg/dl or less
than half of average BG
Therapy Scorecard Screen 2
Monitors carb intake, TDD, basal/carb bolus balance, correction bolus%
14 Day Average:
Carbs
TDD
Meal
Corr
Basal
206 g
48.58 u
38.07%
4.95%
56.98%
Boluses taken? Low carb diet?
Guides therapy – A1c, lows, etc
Carb bolus %
Correction less than 8% of TDD?
Basal at least 40 to 45% of TDD?
Check Correction Bolus %

If correction boluses make up more than 8% of the
TDD (and lows are NOT a problem):
 Move half of the excess units above 8% into basal
rates or carb boluses
 Raise the basal rates
 Lower the carb factor
 Or stop skipping carb boluses
Example: Correction Boluses Over 8%
10 Day Average:
Carbs
TDD
Meal
Corr
Basal
175 g
54.1 u
36%
21%
43%
Over 8%
Move 1/3 to 1/2 of the overage to basals or carb boluses:
 21% of 54.1 = 11.3 units, 8% of 54.1 = 4.3 units
 11.3 u - 4.3 u = 7 units excess
 1/3 to 1/2 of 7 u = 2.3 to 3.5 u to add to basals or carb boluses
Therapy Effectiveness Guides
TDD –
Raise for frequent highs or high A1c
Lower for frequent lows or for frequent lows and highs
Basal/Bolus Balance – about 50% of TDD
Correction Factor = ~ carb factor X 4.4 (mg/dl), carb factor / 4 (mmol)
Correction Bolus % – if over 8% of TDD, move excess into basals or carb
boluses
Average BG – < 160 when checking before & after meals, < 140 when
checking mainly before meals
Standard Deviation –
Keep less than 1/2 of avg BG or below 65 mg/dl
Pump Control Tips
High BGs? Keep The Usual Suspects In Mind
 I ate too much
 Bad infusion set or site
 Inaccurate carb counts
 Missed or late boluses
 Bad insulin
 Stress hormone rebound
 Empty refrigerator syndrome
 Stress, pain, steroid meds
Bad Infusion Set Or Site
If you have “unexplained” highs:
 How often do they happen?
 Do they correct only when you replace your
infusion set?
If you answer yes:
•
Always use tape to anchor the infusion line
•
Consider changing to a different infusion set
The right infusion set and good site technique prevents headaches
and improves your A1c
Tape The Tubing!!!
Put 1” tape on the infusion line to stop Teflon tugs
• Tape the tubing down to stop movement of Teflon
catheter under the skin
No anchor!
• Stops “unexplained highs”
caused when insulin
leaks back to surface
• Less skin irritation
• Prevents pull outs
Lose tape not insulin!
Tape The Tubing!!!
Lose tape not insulin!
Photo courtesy of [email protected]
Use Sterile Technique For Site Prep
30% of people are constant staph carriers and 25% are
intermittent. MRSA is now common. Prevent
infections:
•
Wash hands
•
Sterilize skin with IV Prep
•
Place bio-occlusive IV3000 over site
•
Insert infusion set through IV 3000
•
Steps for staph carriers:
•
Use antiseptic soap all over body once every 1-2 weeks
•
Occasionally, apply bacitracin ointment to inside of nose
Pump Settings That Affect Control
Important Pump Settings
 TDD – adjust when having frequent lows or highs
 Basal % – basal/bolus balance, secure sleep
 Basal rate variation – large variation not physiologic
 Carb factor – postmeal control
 Carb factor variation – may indicate basal problem
 Correction factor – lower high BGs safely
 DIA – bolus accuracy, HypoManager
CDA1 Study
Carb Factors From Cozmo CDA Study
10
7
115
20
 Note how actual carb factors
are distributed in blue
 They are NOT bell-shaped!!!
 People prefer “magic” numbers
– 7, 10, 15, and 20 (grs/unit) –
for their carb factors
 A normal, bell-shaped,
physiologic distribution is
shown in green
 MANY “magic” carb factors are
inaccurate
J. Walsh, D. Wroblewski, and TS Bailey: Insulin Pump Settings Ğ A Major Source For Insulin Dose Errors,
Diabetes Technology Meeting 2007
Carb Factors From CDA1 Sudy
 Graph shows carb factor
versus TDD for 200 pumps
with better control (avg BG <
209 mg/dl)
 Note a break in relationship
(red line) near a TDD of 40
u/day or carb factor of 10
 Suggests that people are
hesitant to lower carb factors
below 10
CDA1 Carb Rule #s Compared To PI
450 Rule
(40%
basl)
TDD
500 Rule
(50%
basl)
550 Rule
(60%
basl)
CrbF <40
BG <209
Rule# Crb F
<40 BG<209
20.0
22.5
25.0
27.5
20.6
412.0
25.0
18.0
20.0
22.0
18.3
456.3
30.0
15.0
16.7
18.3
15.9
477.0
35.0
12.9
14.3
15.7
13.6
474.3
40.0
11.3
12.5
13.8
11.2
448.0
45.0
10.0
11.1
50.0
9.0
60.0
CrbF >40,
BG <209
Rule# CrbF
>40 BG<209
Carb Rule #s
450-475
10.9
437
12.2
10.5
474
10.0
11.0
10.2
508
7.5
8.3
9.2
9.4
563
70.0
6.4
7.1
7.9
8.6
603
80.0
5.6
6.3
6.9
7.8
627
90.0
5.0
5.6
6.1
7.1
636
100.0
4.5
5.0
5.5
6.3
630
475-625
The average carb factors in the blue boxes are those used in pumps
with better control where the avg BG was 209 mg/dl or less.
TDDs are shown in the tan box on the left.
CDA1 Basal/Bolus Balance
Qu i c k T i m e ™ a n d a
T I F F (Un c o m p re s s e d ) d e c o m p re s s o r
a re n e e d e d t o s e e t h i s p i c tu re .
 As TDD rises, basal percentage
falls slightly from 51.7% at a
TDD of 20 u to 49.4% at 40 u
and 48.3% at 80 u
 Basals vary widely – 27% to
83% of TDD
 Many basal rates do not appear
to be accurate
 If correction bolus excess is
distributed evenly into basals
and carb boluses, “real” basal
rates would average over 50%
of TDD
J. Walsh, D. Wroblewski, and TS Bailey: Insulin Pump Settings Ğ A Major Source For Insulin Dose Errors,
Diabetes Technology Meeting 2007
Walsh-Roberts Rules For Optimum Readings
 Starting TDD = (TDD X 0.9) + (wt [lbs]/4* X 0.9) **
2
 Keep Basal/Bolus Balance near 50/50
 Basal test – rise/fall less than 30 mg/dl (1.7 mmol) over 8 hrs
 500 Rule for Carb Factor
 2000 Rule for Correction Factor (110 Rule for mmol)
 Set DIA at 4 to 6 hrs
 Keep correction boluses less than 8% of TDD
* or kg/1.8
** If current TDD less than wt/4 with good control, TDD = current TDD X 0.90
J Walsh and R Roberts: Pumping Insulin, 2006
Delay Eating When BG Is High
Glucose exposure is
reduced when high
readings are allowed to
fall before eating.
Remember:
Test early
Don’t forget to eat on time
Don’t forget you bolused
Duration Of Insulin Action (DIA)
How long a bolus lowers your glucose
Bolus On Board (BOB)
Bolus insulin still active from previous boluses
Problem
Most Carbs Are Faster Than “Rapid” Insulin
An hour later, half of most meal’s glucose
rise has occurred, but 80% of rapid insulin
activity remains
Time over which most meals affect the BG
% bolus activity remaining
Take Home:
Bolus 15 to 30 minutes before meals
From Pumping Insulin
Use extended and combo boluses sparingly
Typical Carb Digestion Times
Food
Digestion Time
water
0m
fruit/veg juice
5-20 m
fruit/veg salad
20-40 m
melons/oranges
30 m
apples/pears
40 m
broccoli/caulif
45 m
raw carots/beets
50 m
potatoes/yams
60 m
cornmeal/oats
90 m
Food
Digestion Time
fish
30-60 m
milk/cot cheese
90 m
legumes/beans
120 m
egg
45 m
chicken
1.5-2 hr
seeds/nuts
2.5-3 hr
beef/lamb
3-4 hr
cheese
4-5 hr
Take Home: Choose combo foods to lengthen carb digestion time
Best Bolus Timing For Carbs
Figure shows rapid insulin
injected 0, 30, or 60
min before a meal
Normal glucose and insulin
profiles shown in the
shaded areas
DO NOT bolus an hour
ahead of your meals!!!
Accurate DIA Prevents Lows
Accurate DIA Time
Accurate BOB
Accurate Boluses
Accurate HypoManager
Prevents Lows
Short DIAs Hide Bolus Insulin Activity
A short DIA hides true BOB level and its glucoselowering activity
 Causes “unexplained” lows
 Leads to incorrect adjustments in basal rates, carb factors,
and correction factors
 Or user starts to ignore “smart” pump’s advice
Set DIA based on real insulin action time.
Do not modify DIA time to fix a control problem.
Duration Of Insulin Action (DIA)
Glucose-lowering Activity
Accurate boluses require an accurate DIA
DIA times shorter
than 4 to 7 hrs
will hide BOB and
its glucose
lowering activity
0
2 hrs
4 hrs
6 hrs
Large Doses, Longer Duration
 Large doses (0.3 u/kg or
30 u for 220 lb. person)
of “rapid” insulin in 18
non-diabetic, obese
people show significant
activity beyond 4 hours.
 Medium doses (0.2 u/kg
or 10 u for 110 lb.
person) show similar
results.
Large doses may lengthen
DIA
Apidra product handout, Rev. April 2004a
Dose Size May Affect Duration Of Action
For a 154 lb or 70 kg
person:
0.05 u/kg = 3.5 u
0.1 u/kg
0.2 u/kg
0.3 u/kg
= 7u
= 14 u
= 21 u
Woodworth et al. Diabetes. 1993;42(Suppl. 1):54A
But Studies Routinely Underestimate DIA
 To measure pharmacodynamics,
glucose clamp studies are done
in healthy individuals
 SQ doses from 0.05 to 0.3 u/kg
 But injected insulin ALSO
SUPPRESSES normal basal
release from the pancreas
(grey area in figure)
 Unmeasured basal suppression
makes smaller boluses appear to
have a shorter DIA
 When basal suppression is
accounted for, true DIA times
become longer
Recommended DIA Times
4 hr Linear
4 hr Curvilinear
A DIA of 4 to 6
hrs gives best
estimate for
residual bolus
activity
A longer DIA is a
safer DIA
From Pumping Insulin, 4th ed., adapted fom Mudaliar et al: Diabetes Care, 22: 1501, 1999
DIA Time Selection
Current limited research suggests that DIA times are NOT
different between children and adults
Immediate factors can change insulin action time:
 Shorter with activity and exercise
 Shorter in hot weather
 Longer with fat in diet
Do not change DIA time for temporary factors
DIA Tips
If pump often suggests boluses that are too small, do not shorten the
DIA– it is rarely NOT problem
Instead, ask what is causing the highs and where more insulin is
needed – in basal rates, in carb boluses, or both
DO NOT shorten the DIA for occasional activity. Instead:
• lower boluses or basals ahead of time for planned activities
• or eat more carbs or lower basals for unplanned activities
Basal rates that are too low make the DIA appear SHORT!
How Different Pumps Handle DIA
Differences In DIA Calculations
% Of DIA
Measured
Default
DIA
My
Preferred
DIA
Time
Increment
For DIA
Animas
Curvilinear
2020
100%
4 hrs
4.5 to 6 hrs
30 min
Deltec
Cozmo
Linear
100%
3 hrs
4 to 5.25 hrs
15 min
Insulet
Omnipod
Linear
100%
4 hrs
4 to 5.5 hrs
30 min
95%
6 hrs
5 to 6 hrs
60 min
DIA Type
Paradigm
Curvilinear
522/722
Bolus On Board (BOB)
Glucose-lowering activity that remains from recent boluses
An accurate BOB
• Prevents insulin stacking
• Improves bolus accuracy
• Reveals current carb or insulin deficit
Basal insulin is NOT measured by BOB!
aka: insulin on board, active insulin, unused insulin*
* Introduced as Unused Insulin in 1st ed of Pumping Insulin (1989)
BOB Prevents Insulin Stacking
Bedtime BG = 173
Is there an insulin or a carb deficit?
Correction
Dessert
Bedtime BG
= 173 mg/dl
Dinner
6 pm
8 pm
10 pm
12 am
BOB Is Present In 65% Of Boluses
CDA1 Study Results
Of 201,538 boluses, 64.8% were
given within 4.5 hrs of a
previous bolus
4.5 hrs
An accurate DIA shows that
BOB is present for MOST
boluses
Take Home: insulin stacking is a common threat
J. Walsh, D. Wroblewski, and TS Bailey: Disparate Bolus Recommendations In Insulin Pump Therapy.
AACE Meeting 2007
Blind Boluses Hide BOB
100
90
80
70
60
50
40
30
20
10
0
89.8
57.7
32.5
85.8% blind boluses
% of Boluses with BG or Carb Inputs
14.2
With BG or
carb
With carb
With BG
With BG and
carb
 In 2005, only 28,969 of
117,711 carb boluses given
by 541 pumps across the
US were accompanied by a
BG value.
 6 of 7 carb boluses are
blind – given with no BG
 With no BG, BOB cannot
be accounted for by the
pump in most carb boluses
J. Walsh, D. Wroblewski, and TS Bailey: Disparate Bolus Recommendations In Insulin Pump Therapy.
AACE Meeting 2007
Before giving a bolus,
check your BOB (via BG).
Do not give blind boluses.
BOB Is BOB
If BOB is present, it doesn’t matter how it got there.
Safety requires that BOB be subtracted from
BOTH carb and correction boluses to avoid
hypoglycemia.
BOB is measured only
when a BG is entered into pump!
How Different Pumps Handle BOB
What’s In BOB And What Is It Applied Against?
BOB Includes
This Type Of Bolus
BOB Is Subtracted From
This Type Of Bolus
Carb
Correction
Carb
Correction
Animas 2020
Yes
Yes
No*
Yes
Deltec Cozmo
Yes
Yes
Yes
Yes
Insulet Omnipod
No
Yes
No
Yes
Medtronic Paradigm
Yes
Yes
No
Yes
* Except when BG is below target BG
Different Pump Bolus Recommendations
units
4
Bolus recommended by each pump when: BOB = 3.0 u and 30 gr.
of carb will be eaten
at these glucose levels
3
Carb factor = 1u / 10 gr
Corr. Factor = 1 u / 40
mg/dl over 100
Target BG = 100
TDD = ~50 u
2
1
0
60
90
120
Deltec Cozmo
150
180
Animas 1250
210
240 mg/dl
Medtronic 522
Omnipod cannot be determined here - it counts only correction bolus insulin as BOB
Recommended Bolus Errors Can Be Corrected
30
3.0U
30 gr
160
3U
1.5U
4.5U
A Paradigm user
can scroll down 3
times to see active
insulin, then adjust
dose:
3
+ 1.5
- 4.5
- = 0 u bolus
HypoManager
Shows current insulin OR carb deficit
HypoManager
Compares BOB to correction bolus need:
 When BOB is smaller –> all pumps recommend a
correction bolus
 When BOB is larger –> Cozmo recommends eating
carbs
A very helpful feature:
•
Shows current carb OR insulin deficit
•
Reduces overeating when BG is low
•
Warns when carbs may be needed later even though
current BG is OK or high.
HypoManager
Helps TREAT lows
 Encourage users to test when low
 The BG reading triggers what should be an
accurate recommendation for carb intake to
treat that low
 Prevents ETRS – “Empty The Refrigerator
Syndrome”
 Don’t use with Symlin, ?gastroparesis
Continuous Monitors
CGM Benefits
 Increased sense of
security
 Immediate feedback –
look and learn
 Control with safety
 Worth out of pocket cost
for many
 Reimbursement gradually
catching on
Continuous Monitor
A continuous monitor (OR
frequent meter checks) can
assist optimum energy flow
Optimum BG range
for energy flow
Plus Insulin Pump
With full BG record, basals and
boluses can be adjusted to
provide optimum fuel flow
Optimum BG range
Continuous Monitoring
Benefits
• Lots more info
• Alarms to
prevent lows
& highs
• Security in
knowing where the BG is
and where it is going
• Trends shown by graph,
arrows, or predictors
Limitations
• Accuracy
• Data gaps
• Insurance coverage
• Occ cell phone and
other interference
Continuous Monitor Tips
CGM: Look And Learn
Excess night basal or bedtime bolus
Breakfast bolus too small or too late
Lunch bolus too small or afternoon
basal too low
No Two Points Are Created Equal!
Lower Risk
Going Up
90
Glucose (mg/dl)
Higher Risk
Going Down
100
80
70
60
50
40
30
20
0
50
100
Minutes
150
200
Level of a BG’s risk depends on its trend
Turnaround Time
A Glucose in Motion Stays in Motion
Don’t Stack Insulin
Stay Between The Lines
As readings improve, bring the upper glucose target alert line down
Continuous Monitoring Tips
 Be patient, have realistic expectations
 Don’t panic when meter and
sensor differ
 Expect some lag time
 Don’t react too quickly and stack your insulin
 Look at trends, not just individual values
 Rapid rises usually mean more insulin is needed
 Validate your readings with a meter
Comparison Of Two Continuous Monitors
The Dexcom STS 3 Day & Paradigm RT continuous monitors were worn at
the same time by one person with Type 1 diabetes. With low alert at 80
mg/dl and high alert at 160 mg/dl, 262 readings from Ultra meter
performed over 33 days. Ultra tests done:
•
•
As soon as either monitor’s low or high alert sounded
When values between the monitors disagreed
•
And at routine intervals, including calibrations
Screens show same 3 hr time period (0 to 400 mg/dl), Ultra reading was 73 mg/dl.
GlycensitTM Analysis
B
A
Simultaneous comparison vs 262 Ultra readings over 33 days
1.
2.
3.
Blue dotted lines = ISO meter standard
Yellow area = 95% of all data points
Red lines = min and max deviation by star points
Ideally, all readings would fall between the blue dotted lines
http://tomcatbackup.esat.kuleuven.be/GLYCENSIT/
Which Monitor Alerted First?
Which Monitor Alerted First?
Monitor A Monitor B
Ties
For BGs less than 80
28
1
8
For BGs over 160
25
2
10
This table shows which monitor alerted at least 5 min earlier for true lows and
highs.
Monitor A was first to alert for readings below 80 mg/dl 76% of the time, B was
first 3% of the time, with 21% as ties.
Monitor A was first to arlert for readings above 160 mg/dl 68% of the time, B
was first 5% of the time, with 27% as ties.
More On Monitor Accuracy
Navigator 5 day (shown in
graph)1
 Median ARD = 9.3%
 Clark error grid
 A: 81.7%
 B: 16.7%
 C and D: 1.7%
Dexcom 7-day (not shown):
 Median ARD = 17%
 Clark error grid
 A: 70%
 B: 28%
 C and D: 3%
1
R L Weinstein et al: Diabetes Care, 30, 1125-1130, 2007
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