12/15/2011

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Sensors and Pumps: Where are We in 2011?

Presented by: W. Kenneth Ward, MD Acknowledgements: Kathryn Hanavan, RNP, Matthew Breen, Frank Schwartz MD

Glucose Sensors

• Measure glucose in tissue fluid, typically in abdomen

• Provide glucose value every 1-5 minutes

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Use of Glucose Sensors

Temporary use

– Determine glucose patterns on present therapy

– Can also give patient experience before purchase

Permanent use

– Patients with very high variability

– Severe hypoglycemia esp with unawareness

– Problems with exercise

– High A1C values despite good monitoring effort

Glucose Sensors - DexCom

• Approved for 7 days of use

• Calibration

– every 12 hrs

• Provides glucose value every 5 minutes

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Glucose Sensors – Medtronic

• Calibration

– every 12 hrs

• Provides glucose value every 5 minutes

How Can CGM Improve Control?

• Patient uses trends to anticipate problems

• Use alarms to protect against highs and lows

• Learn from the patterns it can demonstrate – Response to certain foods

– Response to exercise

– Changes with emotional stress

– Etc

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Issues in Using CGM

• Must continue to do SMBG to calibrate

• Not approved to replace SMBG

• SMBG needed to make decisions about diabetes management

Profiles: Susan overachiever

• Susan is a whiz at math and can rattle off her insulin to carb ratio, her correction factor, her basal rates and when to use a dual-wave combination bolus.

• She likes to keep her BG between 60 and 110 but has many values under 50. She is quite anxious about diabetes-related complications and therefore wants tight control.

• Her husband sometimes finds her with that spacey “glazed look.”

• Often she does not have symptoms even when her BG drops below 60.

• Recent A1c: 5.4%

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Dexcom tracing– Susan was not aware

of the duration of hypoglycemia

Susan

• Recommendation:

• Remember that an A1C of 6.5-7% is associated with VERY LOW risk for long term diabetes complications.

• Accidents are a major risk in people with overly tight control.

• If hypoglycemic unawareness continues to be a problem, consider use of a continuous glucose monitor on a 24/7

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Profiles: Richard • Richard, 19 years old, is equally adept at discussing

his ICR, his CF (sensitivity), his basal rates and can easily do the calculations in his head.

• However, his A1C is 8.4%

• Review of his pump download provides several clues

– 75% of his insulin is basal, 25% is bolus

Review of his CGM record provides several clues:

– Some rapid rises in glucose without bolus

– Many of these rises of glucose late at night

• Further history reveals frequent snacking without bolus, esp when out with friends.

Richard

• Recommendation: take bolus for all meals and snacks

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Profiles: Robert twin of Richard

• Knows ICR and CF (sensitivity), but often forgets to do BG test before eating (though he never forgets to count carbs and give insulin with meal).

• Recommendation: test before meals because the correction factor is not useful unless it is utilized.

Profiles: Jenny • Jenny is a trial lawyer and uses an insulin pump.

• She is very busy with important tasks and often is taking a deposition or arguing a case in court.

• She has had a few incidents when her BG fell to low levels (with no warning) and she forgot her train of thought or got mildly disoriented.

• For this reason, she often purposely reduces her basal and bolus doses when she is busy at work, purposely running high BG, to avoid these embarrassing situations.

• Her A1C is 8.4%

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Profiles: Jenny

• Recommendation:

– Consider the use of a CGM (and calibrate it 3-4 x per day).

– Always have rapid-acting snacks on her person

– Enlist the help of a colleague (who is usually with her) to whom she shares her health problems and who can help her recognize subtle signs of hypoglycemia.

– Test at key, critical times.

Profiles: Julio • Julio is a registered nurse, athlete, and insulin

pumper (A1C 6.5%).

• He knows that exercise reduces his need for insulin and for this reason: – When he starts to jog or play basketball, he turns

down his basal by 30% and when he finishes exercise, he turns it back up again.

– Two weeks ago, after basketball from 8-9 PM, he had a bad insulin reaction during sleep at 11 PM, and had difficulty getting back to sleep.

– Last week, during jogging he became disoriented and ran through a red light, was almost struck by a car.

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Profile: Julio

Problems (1) The onset and offset of insulin are slower than most people think.

(2) After exercise is stopped, the muscles continue to take up glucose for several hours

Recommendation:

(1) Review time course of insulin (lispro, aspart, glulisine).

(2) Reduce the basal rate ~60 minutes before exercising vigorously and continue the reduced basal rate for a period of time after stopping exercise.

(2) Consider use of CGM.

(3) Snacks

• Martin is on “basal-bolus” treatment: Lantus at bedtime and lis-pro before meals.

• He is sleeping poorly, having nightmares, and sometimes he is hot and sweaty at night.

• He would like to lose a few pounds

• He wears a Dexcom CGM sensor for one week.

Profile: Martin

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Basal bolus treatment (bedtime Lantus): Dexcom CGM:

CHANGES: --recognized overtreatment of hypoglycemic spell (Rule of 15’s)

--Bedtime Lantus was reduced (vs bedtime snack)

One day, Martin had a really tasty breakfast!

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When unsure of appetite:

(a) take moderate amount of insulin before eating (for

1:10 ICR, take 6 units for 60 grams);

(b) if it turns out that he you eat 40 additional grams,

then add 4 additional units as soon as possible.

Renee’s Problem: periodic very high BG values---

why?

In this case: Oregon Football Games!

--other life stressor, holidays, traveling vacations

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How does pump therapy compare to multiple injections in

type 1 diabetes?

Type 1 diabetic subjects treated by MDI with glargine and after switching to CSII.

Pickup J C , Renard E Dia Care 2008;31:S140-S145

A1C in hypoglycemia-prone type 1 diabetic subjects

when treated by MDI based on glargine and after

switching to CSII.

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Also less hypoglycemia with CSII in this study

STAR 3 TRIAL -2010 (Medtronic)

• In this 1-year, multicenter, randomized, controlled trial, we compared the efficacy of sensor-augmented pump therapy with that of a regimen of multiple daily insulin injections in 485 patients with inadequately controlled type 1 diabetes.

• Patients were supervised by expert clinical teams. The primary end point was the change from the baseline glycated hemoglobin level.

How does the high tech

approach (pump and sensor)

compare with standard multiple

injection therapy?

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STAR-3 trial (adults and children)

• A1C:

– 8.1 % Multiple injections

– 7.5% Sensor-augmented pump

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New ADA Recommendation Regarding CGM

• Continuous glucose monitoring (CGM) in conjunction with intensive insulin regimens can be a useful tool to lower A1C in selected adults (age >25) with type 1 diabetes (A).

American Diabetes Association Diabetes Care 2009; 32:S13-S61

Glucose Sensors

• Are current glucose sensors accurate enough to drive treatment decisions?

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0 20 40 60 80 100

Glucose (mg/dl)

Time (minutes)

Sensor 2

Sensor 1

Blood Glucose

Continuous

Glucose Monitor Hormone delivery

decisions are made by the

algorithm (an elaborate

computer program)

Insulin and

Glucagon Pumps

What is an Artificial Pancreas?

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Insulin AND GLUCAGON

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Glysense

Conclusion

• Pumps and CGM sensors are valuable tools

for management of patients with DM,

especially T1DM

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Questions?

Similar patient from another practice

(Medtronic CGM)