How to order and prescribe a Continuous Glucose Monitor (CGM)?

From the Guidelines

To prescribe a continuous glucose monitor (CGM), first determine if your patient meets the criteria for coverage, typically including diabetes patients on insulin therapy who need frequent glucose monitoring, as recommended by the American Diabetes Association standards of medical care in diabetes 1. When prescribing a CGM, consider the following key points:

• Complete a prescription form specifying the brand (such as Dexcom G6, FreeStyle Libre, or Medtronic Guardian), the monitoring system components needed (sensor, transmitter, receiver), and the duration of use (usually 90 days with refills) 1.
• Include the diagnosis code (ICD-10) for diabetes and document medical necessity in the patient's chart, noting factors like hypoglycemia risk, poor control, or need for intensive monitoring 1.
• Submit the prescription to a medical supply company or pharmacy that handles CGM devices, and provide a letter of medical necessity if required by insurance 1.
• The patient will need training on device insertion, calibration, and data interpretation, which can be provided by your office or the device manufacturer 1.
• CGMs improve diabetes management by providing real-time glucose data and trends, allowing for more timely interventions and better overall glycemic control compared to traditional fingerstick monitoring 1. Some important considerations when using CGM include:
• Sensor-augmented pump therapy can be considered for children, adolescents, and adults to improve glycemic control without increasing overall or severe hypoglycemia 1.
• When CGM is prescribed, intensive diabetes education, training, and support are required for optimal implementation and ongoing use of a continuous glucose monitor 1.
• Persons who have been successfully using continuous glucose monitors should have continued access across third-party payers 1.

From the Research

Ordering and Prescribing a Continuous Glucose Monitor

To order and prescribe a continuous glucose monitor (CGM), the following steps can be taken:

• Determine the medical indication for the CGM, such as frequent, severe, or nocturnal hypoglycemia, especially in the presence of hypoglycemia unawareness 2
• Choose a CGM device that is approved for use in the patient's specific situation, such as a device with an accuracy (%MARD) of approximately 10% that has been approved for self-adjustment of insulin dosages and reimbursement for therapeutic use 3
• Consider the patient's treatment regimen, such as multiple daily injections (MDI) or continuous subcutaneous insulin infusion (CSII), and choose a CGM device that is compatible with their regimen 3
• Evaluate the patient's ability to use the CGM device, including their technical proficiency and ability to interpret the results 2
• Consider the cost and reimbursement of the CGM device, as well as any barriers to use, such as lack of standardization of software methods for analysis of CGM data 2

Clinical Practice Guidelines

The Endocrine Society has developed clinical practice guidelines for the use of CGM, including recommendations for real-time CGM in adult hospital settings, children and adolescent outpatients, and adult outpatients 4

• These guidelines were developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence
• The guidelines evaluate the potential uses of CGM and provide evidence-based recommendations about where CGM can be beneficial in maintaining target levels of glycemia and limiting the risk of hypoglycemia

Alarm Settings and Glucose Outcomes

The alarm settings of CGM systems can have an impact on glucose outcomes in patients with type 1 diabetes 5

• Higher glucose thresholds for hypoglycemia alarms were related to less time with glucose < 70 and < 54 mg/dL, but also higher average glucose levels and less time-in-range
• Lower glucose thresholds for hyperglycemia alarms were related to lower average glucose levels and less time with glucose > 250 and > 320 mg/dL, without more hypoglycemia
• The optimal alarm threshold for < 1% of time in hypoglycemia was 75 mg/dL, and the optimal alarm threshold for < 5% of time in hyperglycemia and hemoglobin A1c ≤ 7% was 170 mg/dL