Diabetes II Insulin pumps; Continuous glucose monitoring system (CGMS) Ernest Asamoah, MD FACE FACP FRCP (Lond) 9501366-011 20110401
Objectives Understand the need for insulin pumps and CGMS in managing diabetic patients. Know what tools are in current use How insulin pumps and CGMS complete the picture of managing diabetes (especially complex and brittle patients
What is an Insulin Pump? A subcutaneous insulin pump is a battery operated device, designed to deliver insulin into the user s body 24 hrs a day according to a preset program. The insulin pump continuously delivers a small amount of rapid acting insulin Aspart or Lispro at a basal rate to help the body to utilize the glucose that is in the blood stream at the time. A bolus dose of insulin can be given to cover the glucose that comes from the carbohydrates that the patient eats and/or to cover a high blood glucose level. 3
What is an Infusion Set? The infusion set is a connection between the body and the insulin pump. The infusion set is composed of a cannula or needle, adhesive dressing, tubing and a connector to the pump cartridge. The infusion set is inserted subcutaneously. The infusion set is usually inserted in the abdomen, but can be placed in other locations, e.g. thigh, back of the arms or the upper buttocks. 4
Infusion Set Continued: 5
An insulin pump and infusion set. The infusion set is shown loaded into a spring-loaded insertion device (the blue object). A reservoir of insulin is shown attached to the set.. 6
Insulin for Pump Rapid acting insulin supplied by UCSF hospital pharmacy Aspart Insulin Lispro Insulin 7
Critical Points Because the pump uses a rapid acting insulin analogue (lispro or aspart), the patient is at risk for developing diabetic ketoacidosis if: the pump malfunctions the set dislodges or kinks the reservoir becomes empty The blood glucose level should be monitored: the patient is eating (before meals, bedtime, 2 am) The insulin pump should be disconnected from the infusion set for: - Mammograms - Bone density tests - Radiation treatment - CT scan - MRI - X-rays The infusion set can remain in place provided it is not metal. The Sure-T and the Detach Infusion set contain metal and must be removed prior to MRI. 8
Insulin pump technology Insulin pump models currently available: Animas 2020 Paradigm real-time MMT-522 Paradigm real-time MMT-722 Accu-Chek Spirit Accu-Chek D-Tron Plus Deltec Cozmo Image reproduced courtesy of Diabetes UK
It s Not Just A1C Reduction: It s How You Get There!
History of Glucose Monitoring Urine Glucose Testing Blood Glucose Meters Continuous Glucose Monitoring FDA approved Professional CGM Device July,1999 Medtronic CGMS 2002-CGMS Gold 2008-iPro FDA approved Personal CGM Devices December, 1999 Glucowatch 2004 Medtronic Guardian 2006 DexCom 2008 Navigator
Glucose Concentration (mg/dl) CGM Reveals Glycemic Variability Masked by A1C 400 Mean A1C 6.7% 9 Type 1 pump patients treated with lispro Patients placed on CGMS Gold for 24 hours Professional CGM revealed excessive glucose variability in well controlled patients 300 200 100 0 12AM 4AM 8AM 12PM 4PM 8PM 12AM A normal to low A1C may be the result of hypoglycemic events Levetan C, et al. Diabetes Care 2003; 26:1-8
Hirsch et al., Journal of Diab and Its Complications 19 (2005) 178-181
Blood Glucose Variability Standard of Care? Greater Frequency and Magnitude of Glycemic Variability Increased Oxidative Stress via Reactive Oxygen Species Despite comparable A1C, conventionally treated patients had markedly higher risk of progression to retinopathy than those treated intensively DCCT finding Glucose Variability, considered in combination with A1C, is a more reliable indicator of blood glucose control and the risk of long-term complications than mean A1C alone Hirsch et al., Journal of Diab and Its Complications 19 (2005) 178-181
Continuous Glucose Monitoring Completes the Picture Fingerstick Testing A1C The addition of continuous glucose CGM monitoring to SMBG and A1C may help improve outcomes
Three Studies In One: Children, Adolescents and Adults Children: 8-14 years of age (n = 114) Adolescents: 15-24 years of age (n = 110) Adults: 25 years of age (n = 98) The study was large enough so that each age group had enough subjects to demonstrate statistical significance Total Number of Patients in Study = 322 The Juvenile Diabetes Research Foundation Study Group, N Engl JMed 2008, 359. Published at www.nejm.org on September 8, 2008.
Absolute A1C Reduction (%) Primary Outcome Adults, Adolescents & Children A1C reduction was significant for Adults who used Personal CGM Adults Adolescents Children 0.10 Personal 0.00 CGM SMBG Only +0.02 Personal CGM SMBG Only Personal CGM SMBG Only -0.10-0.20-0.30 P < 0.001-0.18-0.21-0.22-0.40-0.37-0.50-0.60-0.50 P = 0.52 P = 0.29 The Juvenile Diabetes Research Foundation CGM Study Group, N Engl JMed 2008: 359:14, 1464-1467.
Secondary Outcomes: Personal CGM Improved Glucose Control for Adults & Children Relative A1C decrease by 10% Absolute A1C decrease by 5% 26-week A1C level <7.0% Adults ( 25 yrs) P = 0.003 P < 0.001 P = 0.005 26 week A1C level <7.0%, with no severe hypoglycemia P = 0.006 Adolescents (15-24 yrs) Not Significant Not Significant Not Significant Not Significant Children (8-14 yrs) P = 0.04 P = 0.009 P = 0.01 P = 0.02 The Juvenile Diabetes Research Foundation CGM Study Group, N Engl JMed 2008: 359:14, 1464-1467.
Higher Utilization of Personal CGM Leads to Better Outcomes Across ALL Ages Patients within ALL three age groups, including teens and young adults, who used the device at least 6 days a week had substantially lower HbA1c levels after six months compared with patients who used CGM less than six days a week - Analysis presented by JDRF and other investigators at EASD* *JDRF Press Release. September 8, 2008. Posted on www.jdrf.org.
Primary Endpoint: Pediatrics (7 18 years) Improved glycemic control in pediatrics using SAP, including a significant reduction in A1C compared to MDI at 12 months. 8.8% 8.3% 8.3% 8.4% 8.6% 8.5% +0.2 A1C 8.3% 8.3% - 0.5 P<0.001 7.8% 7.7% 7.8% 7.9% -0.4 7.3% 7.5% 0 3 6 9 12 Months = SAP = MDI n = 78 n = 78 Values are means ± SE. Comparisons between SAP group and MDI group are significant for each time period (P<0.001). Berganstal, Richard, Effectiveness of Sensor Augmented Insulin Pump Therapy in Type 1 Diabetes, New England Journal of Medicine. Published June 29, 2010
Primary Endpoint: Adults 19 years 1.0% mean A1C reduction from baseline achieved in the SAP group and sustained over 12 months 8.5% A1C 8.0% 7.5% 8.3% 7.8% 7.8% 7.9% 7.9% -0.4-0.6 P<0.001 7.0% 7.3% 7.3% 7.3% 7.3% 0 3 6 9 12 Months = SAP = MDI n = 166 n = 163-1.0 Values are means ± SE. Comparisons between SAP group and MDI group are significant for each time period (P<0.001).
A1C Reduction Correlates to Increased Sensor Use The majority of patients used sensors 61% of the time Patients who used sensors 81% of the time reduced their mean A1C by 1.2% at 1 year vs. baseline Change in A1C at 1 Year vs Baseline 0-0.5-1 -1.5 Frequency of Sensor Use (% of Time) 21-40% 41-60% 61-80% 81-100% -0.19-0.64-0.79-1.21 n =27 n =46 n =108 n =56 Values are the difference between the means ± SE. p=0.003 for association between sensor wear and A1C reduction at 1 year. Only 7 participants had sensor use of 20% or less, with a change in A1C of -0.43 at 1 year vs. baseline.
Current CGM Technologies
Professional and Personal CGM Categories Continuous Glucose Monitoring Professional CGM Continuous glucose monitoring for healthcare providers Personal CGM Continuous glucose monitoring for patients
Professional CGM Products Available Today ipro CGM Dexcom 9501364-011 ipro is a registered 20110309 Medtronic trademark MiniMed, of Medtronic Inc. 2011. MiniMed, All rights reserved. Inc. Dexcom is a trademark of Dexcom, Inc.
Personal CGM Products Available Today Freestyle Navigator 5 days DexCom 7 Plus 7 days Medtronic Real-Time CGMS or Guardian 3 days Freestyle Navigator is a registered trademark of Abbott Laboratories, DexCom 7 Plus is a trademark of Dexcom, Inc., Medtronic CGMS or Guardian is a registered trademark of Medtronic MiniMed, Inc.
Personal CGM Device Specifics Endocrine Practice Vol 16 No 5 pp 730 744 Sept/Oct 2010
Accuracy of Devices All devices require confirmation fingersticks as well as fingersticks for calibration Most Mean Absolute Relative Difference (MARD) 10%-20% for the different glucose ranges 60%-80% fall in the Clark s A zone error grid Physiologic lag time 5-10 minutes Acetaminophen and Vitamin C may interfere with some of the CGM devices Endocrine Practice Vol 16 No 5 pp 730 744 Sept/Oct 2010
Patient Selection Recommendations
AACE Supports Broad Range of 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 postprandial hyperglycemia Recommended to use Professional CGM on an episodic basis Endocrine Practice Vol 16 No 5 pp 730 744 Sept/Oct 2010
AACE Supports Broad Range of 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. Endocrine Practice Vol 16 No 5 pp 730 744 Sept/Oct 2010
Education is Key to Success Set proper expectations Lag time Not replacement for fingersticks Usage: Intermittent versus full time Time and Patience is required Set alarms off or wide at initial training Follow up crucial
Data Interpretation and Management
Methodology Three Steps to Analyze CGM Reports: Step 1: Look at the overnight period first Step 2: Look at pre-prandial levels Step 3: Look at post-prandial levels
Step 1: Look at the Overnight Period Definition of Overnight Period Night time period no longer influenced by the last evening meal / snack True fasting period is usually midnight to 6 AM Identify fasting values as hypo and hyper Anything below target range is hypo Anything above target range is hyper Target ranges are individually set
Step 1: Look at the Overnight Period First: Look for Hypo For glucose levels BELOW low target Problem: basal rate may be too high Solution: decrease basal rate? Second: Look for Hyper For glucose levels ABOVE high target Problem: basal rate may be too low Solution: increase basal rate?
Step 2: Look at Pre-prandial Periods Definition: Period just before a snack or meal What is seen before a meal? Previous bolus (active insulin) Previous meal residual Post-meal activities Identify glucose values that are hypo and hyper Find the cause-effect relationship of previous meal / bolus / activity Look at breakfast, then lunch, then dinner
Step 2: Look at Pre-prandial Periods First: Look for Hypo Consider: Influence of bolus, previous meal, active insulin Exercise and activity Food: Timing, Quantity, Composition Second: Look for Hyper Consider: Same considerations as hypo Plus breakfast related dawn phenomenon
Step 3: Look at Post-prandial Periods Definition: 3-hour period following food intake Peak values should be lower than 135-180 mg/dl (~30-60 mg/dl of pre-meal value) What is seen after a meal? That meal s bolus (active insulin/insulin on board) Previous meal residual Post-meal activities Identify glucose values that are hypo and hyper Identify the cause-effect relationship of previous meal / bolus / activity Look at breakfast, then lunch, then dinner (and major snacks)
Step 3: Look at Post-prandial Periods First: Look for Hypo If hypoglycemia is observed in the PP period (2 3 hours after meal): Consider issue with the bolus for that meal Consider timing, type, accuracy of bolus Consider influence of exercise Second: Look for Hyper If Hyperglycemia peaks above 180 mg/dl post meal: Consider timing, type, accuracy of bolus Consider food intake, food quantity and meal composition
Case Study 1
Case 1: CGM Added to Current Pump Therapy 17 year old female with T1DM, current A1C = 7.2% Complaints of night sweats, early morning low and high blood sugars, feeling lethargic early in the morning and throughout the day Checks her blood sugar 4-6 times per day Currently using an insulin pump with insulin lispro Pump settings: Basal 12 MN 2:30 AM 4:30 AM 6:30 AM 3 PM 7 PM 0.7 0.65 0.6 0.5 0.35 0.45 Units/hr Carbohydrate ratio: 1:17 Sensitivity 1:100
Case 1: Professional CGM Report
Case 1: Professional CGM Report What is the main problem shown through the sensor tracings? 1. No changes need to be made 2. Need to change insulin 3. Post-meal excursions are the dominant problem of this patient 4. Nocturnal hypoglycemic unawareness 5. 2 and 3 6. All of the above
Case 1: Professional CGM Report What adjustment might be made? 1. No changes need to be made 2. Increase the insulin to carbohydrate ratio 3. Decrease the overnight basal rates by 0.05 units/hour 4. Increase the daily basal rate
Case 1: Addition of CGM Patient added CGM to her pump therapy Patient has continued to check her blood sugar approximately 4-6 times per day Her pump settings: Basal: 12 MN 2:30 AM 4:30 AM 6:30 AM 3 PM 7 PM 0.65 0.6 0.55 0.45 0.4 0.45 Units/hr Carbohydrate ratio: 1:15 Sensitivity: 1:100 Labs: A1C = 6.8%
Postprandial Preprandial Overnight Period
Case 1: Interpretation What did you learn from this report? 1. Trending shows high postprandial blood sugars 2. Trending shows preprandial lows 3. Trending shows hypoglycemic excursions early morning 4. No issues 5. All of the above
Case 1: Management So what might need to be done? 1. Decrease insulin-to-carbohydrate ratio for lunch and dinner 2. Discuss with patient why she feels it necessary to override the bolus wizard 3. Increase the overnight basal rate 4. 1 and 2 5. All of the above
Questions? Thank you