Benefits and Drawbacks of Continuous Glucose Monitoring System
Benefits: CGMS is able to provide a more complete picture of a person’s daily glucose levels with up to 288 glucose readings per day. As such, the patient has the immediate benefit of reducing any time spent at hypo- or hyperglycemic levels, and patients spend more time in the target range. Long term, with patients better equipped to address glucose levels throughout the day, coverall A1C levels will be better regulated and reduce the risk of future complications.
Drawbacks: The accuracy of the device is highly dependent on calibration with traditional SMBG diagnostic tools, and this adds a level of inconvenience to users. In addition, patients and physicians are still pondering the benefits of more data points and how to best use the data.
Why has adoption of CGMS been sluggish?
Though it seems logical to provide diabetics and their treating physician team with as much information as possible, the physician community has not rushed to adopt CGM technology. We believe there are four key reasons for this poor penetration:
1. Reimbursement. We believe the lack of reimbursement by the insurance companies has been the highest hurdle for CGM. However, most of the payors added CGM to policy over the past 12 months and/or loosened requirements to gain covered access to CGM. With approximately 75% of the lives now covered, we believe the reimbursement hurdle has effectively been removed.
2. More work for specialists that don’t have the time: With the growing influence of physician groups and the impact of managed care, doctors are already on a schedule which requires high daily patient volume in order to generate sufficient dollars. Considering the endocrinologist will likely spend 10-15 minutes with a diabetic patient, having that patient bring along up to 20,000 CGM readings to be analyzed is likely not desirable. To add to this issue, the endocrinologist is not able to bill for any CGM-related work.
3. Accuracy still requires use of SMBG: CGM technology has improved significantly from its earlier iterations. Regardless, CGM users are still required to calibrate their results using SMBG and the technology is only indicated for use as an adjunct to conventional blood glucose monitoring. That said, we believe the true value of CGM lies in its ability to provide blood glucose trends rather than single-point measurements.
4. Failure of earlier devices: In April 2002, Cygnus (which was later acquired by Animas) launched the GlucoWatch, the first device offering continuous glucose monitoring capabilities. The device, which is no longer being promoted but is still available for sale in the US, is worn on the wrist and measures glucose levels non-invasively by drawing fluids from the skin via an electric current. Though the device was promising, clinical results were disappointing. Patients complained that the device was bulky, caused skin irritation, and had accuracy problems. Furthermore, the first-generation CGMS devices (DexCom, Medtron, and Abbott) were not user friendly and experienced quality issues, further souring patients on the concept. The high cost and low performance was not enticing.