Do the benefits of CGM justify the current cost in type 2 diabetes care?
Continuous glucose monitoring is useful for anyone with type 2 diabetes, even when benefits are subtle.
When I transfer what we learned as educators and clinicians from blood glucose monitoring to CGM, the lessons are similar. With CGM, people using insulin, whether with type 1 or type 2 diabetes, derive great benefit. We certainly use CGM for people with type 2 diabetes prescribed multiple daily injections. In the MOBILE study, we showed how much CGM could help people using basal insulin, though I believe, with more training, we could have done even better.
For those with type 2 diabetes prescribed non-insulin therapies, data suggest intermittent use of CGM can help people understand the impact of lifestyle on their glucose level, get a sense of their postprandial glucose and change behavior. I have so many patients with type 2 diabetes not on insulin who tell me CGM has changed how they eat and exercise. It ties into lifestyle. But that is hard to quantify, and those changes may or may not translate to a lower HbA1c. It is my hope that those patients are less likely to develop cancer or cardiovascular disease by having less glycemic variability and a healthier lifestyle.
The benefits can be more subtle in this population. It is easy to show a hypoglycemia reduction benefit with CGM use or diabetic ketoacidosis prevention. Showing long-term improvements for anything that is lifestyle-based would require a large, long-term study. I am always surprised by what I see when I put a CGM on someone with type 2 diabetes. There are many domains where CGM could help, but we certainly do not have the data proving so.
Two things are going to happen. Intermittently scanned CGMs will soon become consumer tools that can be purchased over the counter. There may be a real patient-driven use of these devices, especially when they do not require a prescription, like with glucose meters. Then, we need to conduct the research on outcomes improvement, and we must define what that means. I would look at patient adherence and advancing or intensifying diabetes therapy as endpoints. That will be challenging.
People with diabetes must have access to CGM, but providers must know what to do with the data. That requires education. CGM is useless otherwise.
Anne L. Peters, MD, is professor of clinical medicine at Keck School of Medicine at the University of Southern California, Los Angeles.
We do not have the evidence we need demonstrating cost-effectiveness of CGM for people with type 2 diabetes.
As a general internist, I often see patients with type 2 diabetes struggle with managing frequent blood glucose checks along with insulin injections. For people prescribed multiple daily injection therapy, CGM can decrease barriers to checking glucose, making things a little easier.
For the type 1 diabetes population, there are several studies, mostly using data from a few clinical trials, that demonstrate the utility and cost-effectiveness of CGM, though one could argue the data are not real world. Unfortunately, there are no good data that answer this question for the type 2 diabetes population.
Cost-effectiveness is not the same as cost savings. Cost-effectiveness means the intervention will cost more to achieve a desired outcome, but the intervention is worth it — valuable for increasing the combination of both quality of life and length of life. This is what we call quality-adjusted life-years. We already hear the health care system costs too much. Ideally, you want an intervention that is cost saving, not cost-effective.
The MOBILE study demonstrated an HbA1c benefit among people with type 2 diabetes using basal insulin and CGM, but the benefits translated to about half a percentage point. In the DIAMOND trial with a type 1 diabetes population, the HbA1c benefit of CGM was 1 percentage point. That half a percentage point could be a big difference, and that difference may drive a decreased cost-effectiveness compared with type 1.
There are downstream benefits. Studies suggest CGM use is associated with a decrease in hospitalizations. If you include those dollars in the cost-savings models, that does help. However, the major driver right now is the cost of CGM. If market forces can drive down cost, that would help. If implementation was more effective — a better improvement in HbA1c, a sharper decrease in hospitalizations — that would help.
Sometimes when an intervention seems to work, people apply it to a broader population than it was intended for, even when the intended effect is not as good. The question we must ask is how do we get people to use CGM to its maximum benefit?
Neda Laiteerapong, MD, MS, FACP, is an associate professor in the section of general internal medicine, director of primary care behavioral health integration and director of Primary Care Investigators in Chronic Disease and Health Disparities (PITCH) at the University of Chicago.