Initiating and Utilizing Flash CGM in Clinical Practice

Abstract and Introduction

Abstract

Use of continuous glucose monitoring (CGM) has been shown to improve clinical outcomes in patients with type 1 diabetes (T1D) and type 2 diabetes (T2D), including improved glycemic control, better treatment adherence, and an increased understanding of their treatment regimens. Retrospective analysis of CGM data allows clinicians and patients to identify glycemic patterns that support and facilitate informed therapy adjustments. There are currently 2 types of CGM systems: real-time CGM (rtCGM) and flash CGM. The FreeStyle Libre 2 (FSL2) is the newest flash CGM system commercially available. Because the FSL2 system was only recently cleared for use in the US, many endocrinologists and diabetes specialists may be unfamiliar with the strengths, limitations, and potential of the FSL2 system. This article focuses on practical approaches and strategies for initiating and using flash CGM in endocrinology and diabetes specialty practices.

Introduction

The benefits of continuous glucose monitoring (CGM) have been demonstrated in large clinical trials^[1–4] and numerous real-world, observational studies.^[5–15] On the strength of this growing body of evidence, use of this CGM is recommended for most individuals with diabetes who are treated with intensive insulin regimens.^[16]

CGM technology first emerged as real-time CGM (rtCGM); however, flash continuous glucose monitoring (flash CGM), another method of CGM, is being adopted by an increasing number of individuals with type 1 diabetes (T1D) and type 2 diabetes (T2D) for their daily self-management.

Large randomized controlled trials using flash CGM have demonstrated significant improvements in hypoglycemia, glycemic variability, and patient satisfaction in individuals with well-controlled T1D^[3] and T2D^[17] who were treated with intensive insulin therapy. Improvements in glycated hemoglobin A1c (HbA1c) and percentage of time within the target glucose range were observed in T1D^[3] but not T2D^[17] patients. Moreover, recent real-world observational studies have reported significant reductions in hospital admissions for severe hypoglycemia and/or diabetic ketoacidosis in large cohorts of T1D adults who used flash CGM for 12 months.^[6,7] Decreased hypoglycemia frequency, reduced HbA1c, and improved quality of life among young adults with T1D treated with insulin pump therapy have also been demonstrated.^[18]

The FreeStyle Libre 2 (FLS2) (Abbott Diabetes Care, Alameda, CA) is the newest flash CGM system commercially available. Unlike earlier versions of the FreeStyle Libre system, which did not offer alarms, the FSL2 offers optional alarms as an added safeguard against severe hypoglycemia and hyperglycemia. Users can select the times and situations when the alarms are operational, which can help counter "alarm fatigue" and support persistence in their system.

Because the FLS2 system was only recently cleared for use in the United States, many clinicians may be unfamiliar with the strengths, limitations, and potential of the FSL2 system in managing T1D and insulin-treated T2D patients who are treated with intensive insulin management regimens. The aim of this article is to provide practical guidance for initiating and utilizing the FSL2 system in endocrinology and diabetes specialty practices.

Table 1. Targets for assessment of glycemic control: T1D/T2D and older/high-risk individuals [19]
Diabetes group	Time in range	Time below range	Time above range
Within target range	% of readings time/day	Below target level	% of readings time/day	Above target level	% of readings time/day
T1D^a/T2D	70–180 mg/dL	>70% >16 hr, 48 min	<70 mg/dL	<4% <1 hr	>180 mg/dL	<25% <6 hr
			<54 mg/dL	<1% <15 min	>250 mg/dL	<5% <1 hr, 12 min
Older/high-risk T1D/T2D	70–180 mg/dL	>50% >12 hr	<70 mg/dL	<1% <15 min	>250 mg/dL	<10% <2 hr, 24 min

Table 2. Current CPT codes for CGM billing
Code	Description/requirements for billing	Personnel who can perform and bill for service
95249	APPLICATION: • When CGM system is patient-owned SERVICES COVERED: • Sensor placement, hook-up, calibration of monitor, patient training, and printout of recording REQUIREMENTS: • ≥72 hours of CGM data are available for interpretation. • Patient must bring the data receiver into the healthcare provider office where the entire process is performed. • This code should only be reported once during the time the patient owns the device. • Obtaining a new sensor and/or transmitter without a change in the receiver does not warrant reporting subsequent times. • The code should not be reported in conjunction with 99091 and/or 0446T. • The correct date of service is the date the CGM recording is printed in the office. • If a separate and significant evaluation and management (E/M) service is performed on the same date, a modifier 25 may be required to be added to the E/M code.	• Trained RN, PharmD/RPh, RD, CDE, or MA can perform service if within scope of practice. • Billing can be done by supervising physician, advanced practitioner, or hospital outpatient department.
95250	Ambulatory CGM of interstitial tissue fluid via a subcutaneous sensor with a minimum of 72 hours; clinician-owned equipment, sensor placement, hook-up, calibration of monitor, patient training, removal of sensor, and printout of recording. • The code can only be reported one time per month and should not be reported in conjunction with 99091 and/or 0446T. • All elements described in the code description must be performed to appropriately report the code to insurers. • The correct date of service is the date that the CGM recording is printed in the office. • If a separate and significant evaluation and management (E/M) service is performed on the same date, a modifier 25 may be required to be added to the E/M code.	• Trained RN, PharmD/RPh, RD, CDE, or MA can perform service if within scope of practice. • Billing can be done by supervising physician, advanced practitioner, or hospital outpatient department.
95251	This code is used and reported to insurers when clinicians perform an analysis, interpretation, and report on a minimum of 72 hours of CGM data. The analysis, interpretation, and report may be done with data from patient-owned or clinician-owned CGM device. Importantly, the analysis, interpretation and report is distinct from an evaluation and management service and does not include an assessment of the patient or indicate a plan of care for the patient.	• Only MD/DO, NP, PA, and CNS can perform and bill for services associated with this code.

Table 2. Current CPT codes for CGM billing

Code

Description/requirements for billing

Personnel who can perform and bill for service

95249

APPLICATION:
• When CGM system is patient-owned
SERVICES COVERED:
• Sensor placement, hook-up, calibration of monitor, patient training, and printout of recording
REQUIREMENTS:
• ≥72 hours of CGM data are available for interpretation.
• Patient must bring the data receiver into the healthcare provider office where the entire process is performed.
• This code should only be reported once during the time the patient owns the device.
• Obtaining a new sensor and/or transmitter without a change in the receiver does not warrant reporting subsequent times.
• The code should not be reported in conjunction with 99091 and/or 0446T.
• The correct date of service is the date the CGM recording is printed in the office.
• If a separate and significant evaluation and management (E/M) service is performed on the same date, a modifier 25 may be required to be added to the E/M code.

• Trained RN, PharmD/RPh, RD, CDE, or MA can perform service if within scope of practice.
• Billing can be done by supervising physician, advanced practitioner, or hospital outpatient department.

95250

Ambulatory CGM of interstitial tissue fluid via a subcutaneous sensor with a minimum of 72 hours; clinician-owned equipment, sensor placement, hook-up, calibration of monitor, patient training, removal of sensor, and printout of recording.
• The code can only be reported one time per month and should not be reported in conjunction with 99091 and/or 0446T.
• All elements described in the code description must be performed to appropriately report the code to insurers.
• The correct date of service is the date that the CGM recording is printed in the office.
• If a separate and significant evaluation and management (E/M) service is performed on the same date, a modifier 25 may be required to be added to the E/M code.

• Trained RN, PharmD/RPh, RD, CDE, or MA can perform service if within scope of practice.
• Billing can be done by supervising physician, advanced practitioner, or hospital outpatient department.

95251

This code is used and reported to insurers when clinicians perform an analysis, interpretation, and report on a minimum of 72 hours of CGM data. The analysis, interpretation, and report may be done with data from patient-owned or clinician-owned CGM device. Importantly, the analysis, interpretation and report is distinct from an evaluation and management service and does not include an assessment of the patient or indicate a plan of care for the patient.

• Only MD/DO, NP, PA, and CNS can perform and bill for services associated with this code.