Sensational Sensors Real Time Continuous Glucose Sensors. Marcia Miller RN, MSN ARNP

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1 Sensational Sensors Real Time Continuous Glucose Sensors Marcia Miller RN, MSN ARNP

2 Objectives Identify models of professional and personal CGMS with and without pump tx Discuss evidence based guidelines for use of CGMS in pediatrics and adults. Describe basic functions of CGMS for acceptance and accuracy of sensors. Review software for analysis of BS levels for improved pt outcomes

3 All CGMS Measures levels of glucose in interstitial fluid every 3-5 minutes ISF proven reasonably assessable ISF reflects concentrations in the brain Lag time between serum BS and ISF Cell s Cell s Cell s Cell s Cell s Interstitial fluid Cell s

4 How does the. glucose sensor work? Glucose + O 2 The sensor soaks up fluid from ISF. The fluid contains oxygen and glucose During the initial wetting period (5 minutes), the fluid (glucose and oxygen) diffuses through the membrane and reacts with the glucose oxidase Gluconic Acid + H 2 O 2 Electrode Membrane Glucose Oxidase 2e - H 2 O 2H + + O e Sensor - signal End of the reaction, the electrode produces a current that is measured as the sensor signal (ISIG). This energy signal is turned into a glucose number ISIG = the signal

5 Site Differences in Glucose Testing Sensor Interstitial versus Capillary Sensor and SMBG are testing at different sites Interstitial Space Sensor mirrors its reading to match SMBG, a process called calibration Skin Cells Capillary Sensor reading and Meter readings should be 20% of each other.

6 Glucose Concentration (mg/dl) A1C versus Glycemic Variability Patients with average A1C of < 7% (ADA goal) 400 Mean A1C 6.7% AM 4AM 8AM 12PM 4PM 8PM 12AM A normal or low A1C may be the result of hypoglycemic events Amylin internal date (Medtronic Diabetes obtained permission to use)

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8 ipro Models of CGMS Professional Model Blinded so pt cannot see results Pt wears sensor for >48 hrs with easy set up Pt journals food, activity and meds for 3 + days Later downloaded and reviewed with HCP and pt Great visual Detect problems with pt current behavior Ipro with Medtronic and DexCom set to blinded

9 I Professional Blinded CGMS Alternative for pt who cannot take advantage of real time CGMS Easy to put on and use Great visual *Help pt awareness of effects of current regimen Pts with nocturnal hypoglycemia Pts changing to new insulin regimen

10 MDI: Glargine HS and RA at Meals Lab 6.7% A1C

11 Candidates for Professional CGM? Patients with discrepancies between A1C and SMBG Unable to achieve goal with SMBG Patients who are pregnant Insulin requiring patients Type 2 patients with increased CV risk Patients with repeated hypoglycemia Pts not ready for RT-CGMS

12 Professional CGM Service Reimbursement Code Purpose Providers Description Payment Level ($) Professional CGM: CGM technical Training Any HCPs Patient training, hookup, removal, download Can be billed more than once based on payor coverage Medicare: ~ $145* Private: ~ $165** Professional CGM: CGM professional interpretation MD/DO NP/PA Data interpretation Can be used for non face-to-face time Can be billed more than once based on payor coverage Medicare: ~ $38* Private: ~ $40**. Individual coverage depends on insurance plan and clinical situation * PMIC Medical Fees in the U.S **All payment levels are estimated average based on Medtronic internal EOB data (October 2008)

13 Real Time CGMS Stand alone Dex Com Seven Plus Guardian RT(Medtronic) FreeStyle Navigator (Abbott DC d in USused internationally) Integrated with pump Animas Vibe with Dexcom in future Medtronic Paradigm Pump (522/722 series and Revel= 523/723 series)

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18 All RT- CGMS show. BS level Trends of BS levels Rate of change 1 arrow changing 2-3 mg/min (20mg hour) 2 arrows 4-5 mg/min (30-40 mg hr) Alarms for low and high set points

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21 Patient Perspective from U-Tube

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23 Pump and Sensor Advantages Transmitter is pump Same adv as all CGMS HCP can see everything.. carbs, insulin, BS,Trends Area under/over the curve Predictive alerts Disadvantage Wearing too much?? Information overload Nuisance alarms

24 Many Trails RT-CGMS 1. Eurthicmics Trial (2009 European Ass.) 1. SAP vs MDI/BSM decreased A1C 1.1 % Achieved A1C <7 in 34.1 % pts 2. Real Trend (Diabetes Care 2009) 2. SAP vs Pump/BSM decreased A1C by.96% in pts wearing CGMS >70% time (1/2 children)

25 3.JDRF CGM Study Group CGMS and Intensive Treatment of Type 1 n engl j med 359;14, october 2, 2008 Pump/ MDI + CGMCGM Medtronic, DexCom & Abbott Pump or MDI with SBGM Hypoglycemia didn t differ in tx groups Consistent use of CGMS predicts A1C reduction AGE 6mo A1c CGMS 6mo A1c SBSM %Time Worn

26 Diabetes Care Jan Short and Long Term Effects of RT-CGMS with Type 2 diabetes 12 wks of RT-CGM vs SBGM on Type 2 pts NOT on prandial insulin receiving care from PCP. Improved A1C at 12 wks and sustained at 24 wks 40 wk FU. (without CGMS) No change in any meds just awareness of what effects BS levels

27 AACE CGM Task Force Authors AACE members and CGM thought-leaders Thomas C. Blevins, MD, FACE Bruce W. Bode, MD, FACE Satish K. Garg, MD George Grunberger, MD, FACP, FACE Irl B. Hirsch, MD Lois Jovanovic, MD, MACE Elizabeth Nardacci, FNP, CDE, BC-ADM Eric A. Orzeck, MD, FACP, FACE Victor L. Roberts, MD, MBA, FACP, FACE Objective of Consensus Statement: Provide a credible source of opinions and recommendations on how to best use and succeed with CGM therapy William V. Tamborlane, MD

28 Continuous glucose monitoring (CGM) technology is not only novel, but it can improve the lives of patients who incorporate it into a comprehensive diabetes management plan. -- AACE Consensus Statement on CGM

29 AACE Reviews Clinical Evidence on CGM Professional Can identify undetected hyperglycemia in pregnant women Professional CGM identified minutes/day of undetected hyperglycemia in studies 1,2,3 Effective in improving maternal glycemic control, infant birth weight, and macrosomia risk in women with type 1 or type 2 diabetes 4,5

30 AACE -Ideal Candidates for Professional CGM 1. Pts with type 1 or type 2 diabetes who: are not at their A1C target. have recurrent hypoglycemia or hypo unawareness. 2. All pregnant women with type 1 diabetes. 3. May increase tx adherence for women with type 2 diabetes or insulin-requiring gestational diabetes 4. Intermittent use may be useful for youth with type 1 diabetes who are changing their diabetes regimen or are experiencing nocturnal hypo, dawn phenomenon, hypo unawareness, or post-prandial hyperglycemia. 5. Recommended to use Professional CGM on an episodic basis.

31 AACE CLINIC REVIEWS PERSONAL Can reduce A1C in adult and pediatric patients with type 1 diabetes and A1C > 7.0%, without increasing hypoglycemia in adult and pediatric patients 6,7 In adults and adolescents, more consistent use predicts successful A1C reductions 7 Can reduce hypoglycemia in well-controlled adult and youth patients (A1C<7.0%) with type 1 diabetes, without increasing A1C 8

32 AACE Ideal Candidates for Personal CGM Patients with type 1 diabetes with: Hypoglycemia unawareness or frequent hypoglycemia. A1C above target or with excess glucose variability. Requires lowering A1C without increased hypoglycemia. During preconception and pregnancy. Children and adolescents who have met A1C targets (<7.0%) and who may be highly motivated. Youth with A1C levels 7.0% and are able to use the device on a neardaily basis. Maybe good candidates and trial period of 2-4 weeks is recommended: Youth who frequently monitor their blood glucose levels. Committed families of children (younger than 8 years) especially if the patient is having problems with hypoglycemia.

33 2011 Endocrine Society CGMS Practice Guidelines Children/Adolescents with T1DM > 7yo Use when A1C <7% to help maintain A1C without increased hypoglycemia. Use with children and adolescents with T1DM with A1C >7% who are able to use on daily basis.

34 2011 Practice Guidelines (Continued) Use intermittent personal /professional CGMS when concerned with: Nocturnal hypoglycemia Dawn phenomenon Hypoglycemic unawareness PP hyperglycemia Changes in insulin therapy

35 Practice Guidelines Continued No recommendations for or against with children less 7 yo Adult recommendations the same as pediatrics Not recommended for inpt ICU or Surgical settings due to accuracy concerns, co-morbidities and hypoglycemic risks

36 Setting the Right Expectations For Patients CGM is not a fingerstick replacement - fingersticks are needed to: Calibrate the system Before making a treatment decisions Sensor glucose (SG) and blood glucose (BG) meter values will rarely be identical, however, SG readings are clinically accurate Studies show more improvement in A1C the more frequently you wear it and look at the receiver (Don t put it on and forget about it)

37 Secrets to make Sensors Sensational..Not Frustrating 1. Calibration 2. SG BG with Lag Time 3. Focus on Trends not BS 4. Insertion/ Comfort 5. Wetting 6. Alerts and Alarms 7. Software for interpretation

38 #1 Calibration Pairing of fingerstick (FS) value to ISF space value Teaches sensor to recognize glucose value to responds to electrical current Reference of sensor mathematical algorithm to calculate BS levels of sensors Essential for optimal outcomes/performance of sensor.

39 When Should I Calibrate? 1. *Must be done when BS not changing for Medtronic. Changing BS OK with DexCom. 2. Must be done 2 hrs after insertion, within 6 hrs later and then q 12hrs. 3. Calibrating before bedtime will help you avoid a METER BG NOW during sleep. 4. Can insert sensor and leave for 2+ hours (HS) and turn sensor on later ( in AM). Sensor will ask you to calibrate with in 5 minutes when BS stable.

40 #2. Lag Time Physiologic lag times 5-10 min. & more with rapid change in BS CGMS show relative difference is 10-20% for different BS ranges Only 60-80% in Clarks A- Zone (lower than SBGM) Maybe due to calibrating in home setting.

41 Differences Between Sensor & Meter Glucose Values Why don t they match exactly? Physiologic lag time Technological lag time Sensor glucose values are updated on the pump every 5 minutes Blood glucose (BG) meter Inaccurate meter readings (related to the meter/strip maintenance, poor hand washing and variability in meter technology) Human Error Not calibrating properly (time of BG change, late BG entries, rounding) Not enough calibrations Too many calibrations

42 #3 CGM Trends Take the focus AWAY from the number!

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44 #5: Insertion 45-60º Introducer needle should be pulled out at the same angle it is inserted Hold gently Do not twist or wiggle the needle when removing

45 Key to Success #4: Insertion 90º

46 #5. Insertion Sites Best sites: Abdominal area or hip area Chose a site that is at least 2 inches away from your naval, 2 inches away from your insulin pump site or 3 inches away from any manual injection site Chose a site that is not restricted by clothing Rotate sites Position glucose sensor 5-6 feet from the insulin pump/monitor (to avoid lost sensor)

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48 #5: Wetting Wait minutes for sensor to wet before connecting transmitter. Avoid inserting sensor into areas that have become thick or hardened Lost Sensor and Sensor Error alarms during the 2 hour initialization time are common if the sensor is not properly wetted.

49 # 6. Alerts/Alarms Common Alerts METER BG NOW SENSR END WEAK SIGNAL Instructions Meter fingerstick is needed to update glucose sensor and continue receiving sensor glucose information Glucose sensor is at the end of its 3 day use and needs to be replaced Insulin pump has not received data for a period of time: Move insulin pump closer to transmitter and check connection

50 Alerts /Alarms CAL ERROR BAD SENSOR SENSOR ERROR Make sure glucose is not changing rapidly then recalibrate If during or shortly after start-up then clear it and continue with or redo start-up: Otherwise replace the glucose sensor Out of range reading is detected by transmitter: Clear the alarm If this alarm occurs repeatedly: Change the glucose sensor

51 #6. Alerts/Alarms ALERTS must be managed and personalized. Some are initiating sensor with high sensor glucose alerts OFF.

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53 CGM Considerations for CGMS Start -Dr. Fran Kaufman Predictive Alarm High Initial Setting OFF or 15 min. Hypo Unaware Low OFF or 20 min 30 min. Rate of Change Alarm Rise OFF or > 4.0mg/dl/min Fall OFF or > 4.0mg/dl/min < 4.0 mg/dl/min High Alert OFF or 250 Low Alert 70mg/dl 100mg/dl

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62 Begin with two reports Daily Summary Sensor Daily Overlay Medtronic Carelink Personal and Pro Daily Summary shows information about the number of sensor alerts each day, amount of insulin taken, and carbohydrates eaten.

63 Sensor Overlay Gold: Above Target Gap in Sensor Data Red: Below Target Avg. Sensor Glucose

64 Overnight and Meal Sensor Overlays This graph combines the sensor glucose tracing recorded between bedtime and wake-up. These graphs combine the pre-meal and post-meal sensor glucose tracings. Time food was entered in the Bolus Wizard

65 Therapy Management Dashboard Overview Snapshot of the key patient information on one page Allows HCPs to see sensor glucose, insulin delivery, and key settings in a visual format Specific hypo- and hyperglycemia pattern identification New pump and sensor statistics such as override data and Estimated A1C To generate the Therapy Management Dashboard and Episode Summary, 5 days of sensor and pump data are needed.

66 Statistics Table Avg. BG: Average of all BG meter readings obtained and the standard deviation. Estimated A1C: Calculated using sensor data over the selected reporting period. Estimated A1C = (Avg. SG )/28.7* BG Readings: Average number of BG meter readings obtained per day. Carbs Entered: Average daily carbohydrate intake and the standard deviation. * Nathan, David M., et al. Translating the A1C Assay Into Estimated Average Glucose Values. Diabetes Care. 31(2008).

67 Hyperglycemic Patterns Table Number of Patterns Time of Pattern Notes: The top 3 hyper patterns are listed based on the magnitude of AUC. If two asterisks appear in the title bar, this indicates that there are >3 patterns and refers to a note at the bottom of the page that states Only highest priority shown.

68 Pump Use Table Insulin TDD: Average total daily dose of insulin and the standard deviation. Basal/Bolus Ratio: The ratio of basal to bolus insulin delivered (% of total for each). Manual Boluses: Avg. daily amount of insulin delivered using manual boluses, and the avg. number of manual boluses delivered per day.

69 Pump Use Table (Continued) Bolus Wizard: Avg. daily amount of insulin delivered using the BW, and the avg. number of boluses delivered for food each day. Food: Avg. daily amount of insulin recommended for food, and the avg. number of boluses delivered for food each day. Correction: Avg. daily amount of insulin recommended for correction, and the avg. # of correction boluses delivered each day. Override (+): Avg. daily amount of insulin increased over the recommended amount, and the avg. # of positive overrides each day. Override (-): Avg. daily amount of insulin reduced over the recommended amount, and the avg. # of negative overrides each day.

70 Pump Use Table (Continued) Suspend Duration: Avg. daily time in minutes spent with insulin delivery suspended manually by the user. Res./Site Change: Avg. time in days between reservoir changes based upon manual prime (tubing fill) events, and the avg. time between infusion set changes based upon fixed prime (cannula fill) events.

71 Pump and Sensor Settings

72 Sensor Alerts Predictive Alert is same as Rate of Change but alarms at rate set ( mg/min) esp. helpful if not looking at pump Area under the curve (AUC)- another new measurement!

73 Area Under the Curve (AUC) Provides insight to how long (duration) glucose is high or low and the severity (magnitude) of the excursion Only available with CGM AUC High and Low Limits are set independently AUC= Area under or over set target limits Total number date points

74 AUC Expect small change in an AUC Low value to be more significant than the same change in an AUC High value ZERO: The closer an AUC value is to zero, the closer you are to your target limit APPLES TO APPLES: Identical AUC Set Limits must be used to compare AUC values USAGE: AUC CANNOT be used alone to make specific treatment changes CALCULATING AUC does NOT mean averaging high or low glucose values

75 Sensor Use Table Avg SG: Avg. of all sensor glucose values obtained and the standard deviation. Wear Duration: Avg. amount of time per week with sensor glucose data. Low SG Alarms: Avg. number of low sensor glucose threshold and predictive alerts per day. High SG Alarms: Avg. number of high sensor glucose threshold and predictive alerts per day.

76 Episode Summary Overview Provides a summary of the hypo- and hyperglycemic episodes and events preceding those episodes Offers therapy considerations based on the most common events observed for hypo- and hyperglycemic episodes Offers therapy considerations for other behaviors related to pump, CGM, and BG meter usage

77 Hypo- and Hyperglycemic Episode Bar Charts Total Number of Episodes Threshold Most events occur within 3 hours prior to the episode Preceding Event Number of Episodes Preceded by the Event

78 Event Pie Charts Total Event Occurrences Percentage of Occurrences that Preceded an Episode

79 Event Description Tables Event Percentage of time event preceded total number of episodes Therapy Consideration

80 Other Observations Table Observation Therapy Consideration(s)

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90 Case Studies Lets Practice!

91 Case Studies 1. I PRO 62 yo F T2DM on metformin and TID u500 insulin. A1C Dex Com 3.Medtronic 722& CGMS 56 yo F on MDI Levimer 13 units AM, 12 units PM ;Novolog 1/20 g CHO & correct 1/50 >150 & Symlin 60 mcg AC A1C 5.8% 35 yo male on 722 Medtronic pump for 3 years and CGMS for 6 months p seizure A1C 7.2%

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102 Case #1 Suggestions?

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113 #3 SAP

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119 Suggestions for Case #3

120 CGMS Conclusions Use of CGM require a steep learning curve, so HCP and payers are slow to accept. CGMS is not perfect and can cause frustration for pts and clinicians. Concerns with limited reimbursement for technology itself and HCP time and resources. More Research needed on use in hospital setting.

121 Honoring the past while reaching the Future Compare past to urine testing in the 80 s and acceptance of BSM High amount of education on proper technique for accuracy Need to work with MD s, Patients and Payers and Companies for acceptance CGMS is so similar to moving forward with CGMS.