EPISODE 3
The myth of CGM MARD
with Bob Vigersky, MD, Chief Medical Officer | Medtronic Diabetes and Satish Garg, MD
CGM is widely used by people living with type 1 diabetes and is an integral component of automated insulin delivery (AID) systems, like the MiniMed™ 780G system. MARD has been historically used to evaluate the accuracy of CGM systems. What are the limitations of this metric and how useful is it when evaluating AID system accuracy?
This podcast is intended for healthcare professionals only. Dr. Garg is a paid consultant with Medtronic. Dr. Garg’s comments refer to his experience in his own clinical practice. Individual results may vary.
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Ebekozien O, Mungmode A, Sanchez J, Rompicherla S, Demeterco-Berggren C, Weinstock RS, Jacobsen LM, Davis G, McKee A, Akturk HK, Maahs DM, Kamboj MK. Longitudinal Trends in Glycemic Outcomes and Technology Use for Over 48,000 People with Type 1 Diabetes (2016-2022) from the T1D Exchange Quality Improvement Collaborative. Diabetes Technol Ther. 2023 Nov;25(11):765-773. doi: 10.1089/dia.2023.0320. Epub 2023 Oct 16. PMID: 37768677.
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Vigersky RA, Shin J. The Myth of MARD (Mean Absolute Relative Difference): Limitations of MARD in the Clinical Assessment of Continuous Glucose Monitoring Data. Diabetes Technol Ther. 2024 Mar;26(S3):38-44. doi: 10.1089/dia.2023.0435. PMID: 38377323.
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Garg SK, Potts RO, Ackerman NR, Fermi SJ, Tamada JA, Chase HP. Correlation of fingerstick blood glucose measurements with GlucoWatch biographer glucose results in young subjects with type 1 diabetes. Diabetes Care. 1999 Oct;22(10):1708-14. doi: 10.2337/diacare.22.10.1708. PMID: 10526740.
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Russell et al. Outpatient glycemic control with a Bionic Pancreas in Type 1 Diabetes. NEJM. 2014;371:313-325. Doi: 10.1056/NEJMoa1314474
Important Safety Information: MiniMed™ 780G system with SmartGuard™ Technology with Guardian™ 4 sensor
The MiniMed™ 780G system is intended for continuous delivery of basal insulin at selectable rates, and the administration of insulin boluses at selectable amounts for the management of type 1 diabetes mellitus in persons seven years of age and older requiring insulin as well as for the continuous monitoring and trending of glucose levels in the fluid under the skin. The MiniMed™ 780GSystem includes SmartGuard™ technology, which can be programmed to automatically adjust insulin delivery based on the continuous glucose monitoring (CGM) sensor glucose values and can suspend delivery of insulin when the SG value falls below or is predicted to fall below predefined threshold values.
The Medtronic MiniMed™ 780G System consists of the following devices: MiniMed™ 780G Insulin Pump, the Guardian™ 4 Transmitter, the Guardian™ 4 Sensor, One-press serter, the Accu-Chek™ Guide Link blood glucose meter, and the Accu-Chek™ Guide Test Strips. The system requires a prescription from a healthcare professional.
The Guardian™ 4 Sensor is intended for use with the MiniMed™ 780G system and the Guardian 4 transmitter to monitor glucose levels for the management of diabetes. The sensor is intended for single use and requires a prescription. The Guardian™ (4) sensor is indicated for up to seven days of continuous use.
The Guardian™ 4 sensor is not intended to be used directly to make therapy adjustments while the MiniMed™ 780G is operating in manual mode. All therapy adjustments in manual mode should be based on measurements obtained using a blood glucose meter and not on values provided by the Guardian™ 4 sensor. The Guardian™ 4 sensor has been studied and is approved for use in patients ages 7 years and older and in the arm insertion site only. Do not use the Guardian™ 4 sensor in the abdomen or other body sites including the buttocks, due to unknown or different performance that could result in hypoglycemia or hyperglycemia.
WARNING: Do not use the SmartGuard™ feature for people who require less than 8 units or more than 250 units of total daily insulin per day. A total daily dose of at least 8 units, but no more than 250 units, is required to operate in the SmartGuard™ feature.
WARNING: Do not use the MiniMed™ 780G system until appropriate training has been received from a healthcare professional. Training is essential to ensure the safe use of the MiniMed™ 780G system.
WARNING: Do not use SG values to make treatment decisions, including delivering a bolus, while the pump is in Manual Mode. When the SmartGuard™ feature is active and you are no longer in Manual Mode, the pump uses an SG value, when available, to calculate a bolus amount. However, if your symptoms do not match the SG value, use a BG meter to confirm the SG value. Failure to confirm glucose levels when your symptoms do not match the SG value can result in the infusion of too much or too little insulin, which may cause hypoglycemia or hyperglycemia.
Pump therapy is not recommended for people whose vision or hearing does not allow for the recognition of pump signals, alerts, or alarms. The safety of the MiniMed™ 780G system has not been studied in pregnant women, persons with type 2 diabetes, or in persons using other anti-hyperglycemic therapies that do not include insulin. For complete details of the system, including product and important safety information such as indications, contraindications, warnings and precautions associated with system and its components, please consult https://www.medtronicdiabetes.com/important-safety-information#minimed-780g and the appropriate user guide at https://www.medtronicdiabetes.com/download-library