Continuous Glucose Monitoring
What is Continuous Glucose Monitoring? Blood glucose meters measure glucose in your blood and glucose sensors measure glucose levels in the fluid around the cells They are not exactly the same numbers and that s normal Traditional blood glucose monitoring with a meter looks at only one point in time
The meter doesn t tell you where you ve really been or where you are going CGMs help understand glucose trends, rate and direction of change The results will give you information about what your blood sugar is doing at times when you don t normally check You will learn how diet, exercise, medication and your lifestyle are affecting your blood sugars
CGMS measures subcutaneous interstitial glucose levels CGMS continuously records on an average of every 5 minutes This technology will be crucial in developing a closed loop system The wearer can either see in real time BG values or use retrospective data to download for analysis
400 Typical Daily Patient Log Glucose (mg/dl) 350 300 250 200 150 100 Target Range Glucose Measurement 50 0 12:00 a.m. Breakfast Lunch Dinner Bedtime
CGM Measures Interstitial Glucose CGM devices measure interstitial glucose Interstitial glucose is related to blood glucose, but not exactly the same CGM glucose values typically lag behind BG values The lag time is related to the physiologic delay of the glucose transfer between blood and interstitial compartments Interstitial fluid G G G G G G Blood Vessel
2 Main Categories of CGM* Professional CGM ipro2 Owned by clinicians, offices, hospitals Episodic, intermittent use (3 days) Blinded or masked evaluation Retrospective review by providers Minimal training and set-up time Personal CGM Revel, Dexcom, Guardian Owned by patients On-going use by patients Displays glucose values and alarms that allow for immediate therapeutic adjustments Continuous review of data by patients Requires patient education * AACE CGM Task Force. Statement by the American Association of Clinical Endocrinologists Consensus Panel on Continuous Glucose Monitoring. Endocrine Practice. 2010; 16(5):730 744.
CGM Category Names & Definitions Professional CGM Personal CGM Ownership Length of wear Display of glucose data Healthcare professionals, clinics, hospitals 3 5 days per evaluation; Episodic, intermittent use Blinded or masked data to allow for unbiased assessment of glucose control Typically owned by patients On-going use by patients Continuously displays glucose values and provides alarms that allow for immediate therapeutic adjustments Data analysis Retrospective review by providers Real-time review by patients Patient Training Minimal training and set-up time Requires education on glucose level targets and alarm thresholds
Personal CGM has 4 components Glucose Sensor: Inserted into subcutaneous tissue Transmitter: Connects to sensor Insulin Pump: Records and displays glucose data Software: Personal and Pro Organizes data into reports used for glucose evaluation Personal CGM System Components
See More Excursions with Professional CGM Kaufman Study* 47 pediatrics (A1C > 8.0%), intensive insulin therapy 3-day CGM evaluation + SMBG Number of Glucose Excursions Identified 191 Compared highs and lows identified with CGM and SMBG 42 72 10 Overall Night-time CGM SMBG CGM revealed up to 7x more night-time excursions than SMBG * Kaufman F, Gibson L, et. al. A Pilot Study of the Continuous Glucose Monitoring System. Diabetes Care. 2001; 24(12):2030 2034. Adapted from Kaufman study.
See More Hypoglycemia with Professional CGM Munshi Study* 40 Elderly patients mean age = 75 70% had type 2 diabetes Avg. A1C = 9.3% Patients Who Experienced Hypoglycemia (as detected by CGM) 65% 48% Patient distribution by therapy: 30% Insulin only = 35% Insulin + Orals = 38% Orals = 8% Below 70 mg/dl Below 60 mg/dl Below 50 mg/dl 3-day ipro evaluation + SMBG 93% of hypoglycemic episodes were unrecognized by SMBG or symptoms *Munshi M, Segal A, et. al. Frequent Hypoglycemia Among Elderly Patients with Poor Glycemic Control. Arch Intern Med. 2011; 171(4):362 364. Adapted from Munshi study.
See More Post-Meal Highs with Professional CGM Boland Study* 56 type 1 children with satisfactory A1C 2 and pre-meal glucose near target range 3-day CGM evaluation + SMBG 90 80 70 60 50 % of Peak Post-Meal Glucose Over Target Range 3 > 300 mg/dl 214 300 mg/dl Evaluated peak post-meal glucose levels 40 30 20 10 181 240 mg/dl 0 Breakfast Lunch Dinner CGM revealed that 90% of peak post-meal glucose was above target range 3 (~50% were > 300 mg/dl) * Boland E, Brandt C, et. al. Limitations of Conventional Methods of Self-Monitoring of Blood Glucose. Diabetes Care. 2001; 24(11):1858-1862. 2) Average A1C of 7.7% ± 1.4%. 3) Post-meal target range of < 180 mg/dl. Adapted from Boland study.
See More Data To Help Reduce Risk of Macrosomia Murphy Study* 71 pregnant women with T1 or T2 Two Arms: CGMS and Control Lower A1C in third trimester with CGM Reduced risk of macrosomia with CGM The use of supplementary CGM as an educational tool during pregnancy is associated with improved glycemic control and reduced risk of macrosomia. * Murphy HR, Rayman G, Lewis K, Kelly S, Johal B, Duffield K, Fowler D, Campbell PJ, Temple RC. Effectiveness of Continuous Glucose Monitoring in Pregnant Women with Diabetes: Randomized Clinical Trial. BMJ. 2008;337: a1680 Adapted from Murphy study.
Star 3 Clinical Trial-provides evidence to support the use of CGMS-multicenter, Type 1 ages 7-70 4 times greater reduction in A1C No increase in severe hypoglycemia More usage-better control Early and sustained results
AACE Reviews Clinical Evidence on CGM Professional CGM Can identify undetected hyperglycemia in pregnant women Professional CGM identified 94-390 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 Personal CGM 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 1 Jovanovic L. The role of continuous glucose monitoring in gestational diabetes mellitus. Diabetes Technol Ther. 2000;2(Suppl 1):S67-S71. 2 Yogev Y, Chen R, Ben-Haroush A, Phillip M, Jovanovic L, Hod M. Continuous glucose monitoring for the evaluation of gravid women with type 1 diabetes mellitus. Obstet Gynecol. 2003;101:633-638. 3 Chen R, Yogev Y, Ben-Haroush A, Jovanovic L, Hod M, Phillip M. Continuous glucose monitoring for the evaluation and improved control of gestational diabetes mellitus. J Matern Fetal Neonatal Med. 2003;14:256-260 4 Murphy HR, Rayman G, Duffield K, et al. Changes in the glycemic profilies of women with type 1 and type 2 diabetes during pregnancy. Diabetes Care. 2007;30:2785-2791. 5 Murphy HR, Rayman G, Lewis K, et al. Effectiveness of continuous glucose monitoring in pregnant women with diabetes:randomised clinical trial. BMJ. 2008;337:a1680. 6 Juvenile Diabetes Research Foundation Continuous Glucose Monitoring Study Group, Ramborlane WV, Beck RW, et al. Continuous glucose monitoring and intensive treatment of type 1 diabetes. N Engl J Med. 2008;359:1464-1476. 7 Chase HP, Beck RW, Xing D, et al. Continuous glucose monitoring in youth with type 1 diabetes: 23-month follow-up of the Juvenile Diabetes Research Foundation continuous glucose monitoring randomized trial. Diabetes Technol Ther. 2010;12:507-515. 8 Juvenile Diabetes Research Foundation Continuous Glucose Monitoring Study Group. The effect of continuous glucose monitoring in well-controlled type 1 diabetes. Diabetes Care. 2009;32:1378-1383.
AACE Consensus Statement on CGM 2010 AACE supports broad range of ideal candidates for Professional CGM* Professional CGM Patient selection and usage: Patients with type 1 or type 2 diabetes who: are not at their A1C target. have recurrent hypoglycemia or hypo unawareness. All pregnant women with type 1 diabetes. CGM may also facilitate treatment adherence for women with type 2 diabetes or insulin-requiring gestational diabetes. 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. Recommended to use Professional CGM on an episodic basis. * AACE CGM Task Force. Statement by the American Association of Clinical Endocrinologists Consensus Panel on Continuous Glucose Monitoring. Endocrine Practice. 2010; 16(5):730 744.
ADA 2010 Standards in Glucose Monitoring Three primary techniques to evaluate control- SMBG, A1C,CGM CGM in conjunction with intensive managment can be a useful tool to lower A1C in Adults w/type 1 Ongoing use may also be helpful in children, teens and younger adults CGM maybe a supplemental tool for SMBG CGM may also be beneficial to maintain glycemic control
Success in lowering A1C correlates to an individual s ongoing use of CGM
Ideal Candidates for CGM Professional CGM Patient selection and usage: Patients with type 1 or type 2 diabetes who: are not at their A1C target. have recurrent hypoglycemia or hypo unawareness. All pregnant women with type 1 diabetes. CGM may also facilitate treatment adherence for women with type 2 diabetes or insulin-requiring gestational diabetes. 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. Recommended to use Professional CGM on an episodic basis.
Ideal Candidates for CGM 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 near-daily basis. The following might be good candidates and a trial period of 2-4 weeks is recommended: Youth who frequently monitor their blood glucose levels. Committed families of young children (younger than 8 years) especially if the patient is having problems with hypoglycemia.
Other candidates Blood glucose variability Gastroparesis Insulin-requiring diabetes with or without a pump Behavior modification Type 2 patients on intensive insulin therapy Patients desiring more time in target range Intermittent CGM with Type 2 DM
Insurance Coverage CMS Medicare Part B Coverage in Washington, Idaho, Oregon( CPT codes 95250 & 95251) Blue Cross of Washington/Idaho Blue Shield Medicaid Aetna/US Healthcare United Healthcare Tri West BCBS of Minnesota/Idaho
Ameriben Solutions BCBS of Illinois/Washington Cigna Healthcare All cover for different criteria, Types of Diabetes, sensing allowed per year Check each individual plan
Part 2
Expectations Tracking and trending/pattern management Immediate feedback on diet, exercise and medication Reducing hypo/hyperglycemia Help in understanding A1c, glucose variability Increase time in target range Assessing magnitude of glucose excursions
Expectations Ongoing use in reductions of A1C CGM supports proactive rather than reactive management Can empower patients to optimize control and improve well being
What Not To Expect From CGM Not a technology that can be used to dose insulin CGM can be used as an adjunct to glucose meter NOT a replacement for a glucose monitor Not a device to put on and forget about Not a system that replaces or substitutes for existing diabetes management tools It does not think for the patient!
Remember All CGMS must be calibrated using SMBG and all treatment decisions are based on the meter BG not the CGM BG due to lag time CGMS can be useful in improving glucose control CGMS is a trending device not a treatment device
Patient Teaching Points
Patient Training patpatei Patient success includes: Practice using CGM Experience learning how to react to CGM feedback (highs, lows) Continuing education Follow-up Addressing questions Providing practical solutions Encouragement Success comes with time & experience
Greater Differences In BG & PSG Expect greater differences in BG & SG when glucose is changing rapidly, such as: After a meal, giving an insulin bolus or exercising or When up or down arrows are showing on the pump Teach patients to focus: Less on the actual sensor glucose number and More on the glucose trend (direction / speed of glucose change)
Balance the frequency of alerts and a patient s tolerance for alerts with the value of the information they receive Choose alerts that benefit patient s control Individualize each alert setting to match patient needs Utilize software reports and patient feedback to help with decisions on adjusting CGM settings Start adjustments within a few days of initialization
BG and SG Rarely Match Exactly BG & SG are not expected to match, but Typically the readings are reasonably close (15% to 20% variance) The disparity of 15% to 20% is larger in higher readings: BG = 250 mg/dl (Range difference: 300 mg/dl to 200 mg/dl) BG = 65 mg/dl (Range difference: 52 mg/dl to 86 mg/dl)
Calibrations are Required for CGM to Work What is a calibration? Adjusting a measurement to match an industry reference or standard Industry reference for measuring glucose: BG Meters YSI (Yellow Springs Instrument) How is CGM calibration done? 1 st patient checks BG using glucose meter Next, BG is entered into pump or receiver (manually or wirelessly) Patient determines if BG reading should be used for calibration
CGM is An Adjunctive Therapy to BG Readings Teach patients to always use a BG reading when: Determining any treatment decision Insulin bolus amount Treatment of low glucose
Strategies for Success at Initialization It is difficult to anticipate how an individual will react in response to alerts until they are actually experiencing them. Therefore, it is usually best to minimize alerts at first: Allowing patients to become familiar with CGM, glucose trends and how insulin, food and exercise affect glucose Easing the patient into the CGM experience. This seems to increase patient understanding, success and adoption of therapy Set alert ranges wide at first Concept: Alert patients only when action is needed As patient s knowledge and ability to interpret graphs increases: Tighten alert ranges to allow patient to obtain full benefit of CGM Turn additional alerts ON (one at a time) as needed Timely follow-up in evaluating and adjusting alert settings is key. 37
Anticipating and Alleviating Patient Concerns
# 1 Patient Concern SG Does Not Match BG Possible questions to ask Are calibrations done at right times? Are 2 down arrows showing when they calibrate? Calibrating 3 to 4 times / day? Calibrating on rise or fall? Calibrating too frequently? Are BG meter readings done correctly? Washing hands? Coding meter properly? Large enough sample? Remind patient: BG readings entered within 15 minutes of a previous reading, will replace the earlier reading
# 1 Patient Concern continued Does patient understand SG BG concepts? SG typically lags behind BG Trending of glucose can be more relevant than actual glucose value A 10% to 20% difference is greater in high BG range than in Low range
# 2 Patient Concern: Too Many Alerts! Frequent alerts may be due to inappropriate alert settings or too many sensor alert features being used Check to see if alerts are applicable and if ranges are set appropriately Make sure patient is referring to sensor alerts and not pump alerts e.g. low reservoir, low battery alerts Questions to ask Is patient taking action immediately after first alert? Is the length of time before the repeat alert occurs too short? Is the sensor taped correctly? Could the sensor be moving / pulling-out / electrode drying? If sensor pulls out (>2 mm) the transmitter will shut off, and cause a Lost Sensor alert
Key Take-Aways Leave all alerts OFF, except Low Glucose, at first Turn pertinent alerts on as understanding of CGM increases Allows patient to become aware of glucose fluctuations, trends, patterns Allows patient to observe effects of food, insulin, and exercise Helps prevent information overload Not all alerts and features have to be used! Select which features best meet individual needs Customize settings based on patient feedback & history When first starting a feature - set alert ranges wide Tighten ranges gradually as patient obtains better control Balance benefit of feedback from alerts & live data with frequency of alerts Helps to minimize alerts and alarm fatigue
The Future My Sentry(relay CGM info to a hub ) Animas Vibe(pump and CGM combo) Paradigm Veo Symphony tcgm(sensor above skin) Apps for phones Closed Loop system