CGM in Type 2 Diabetes: What I Learned From the MOBILE Study

Anne L. Peters, MD


June 30, 2021

This transcript has been edited for clarity.

Today I'm going to discuss the MOBILE study, which looked at how effective continuous glucose monitoring (CGM) is in people with type 2 diabetes who are treated with basal insulin. I was one of the principal investigators in this study, and we just published the results in JAMA. Let me explain the study and why I think it's important.

This was a randomized controlled trial done at 15 centers in the United States. What's really important to me is that more than half of these centers were treating patients who are underresourced and ethnically diverse; it wasn't the standard higher socioeconomic status population group. This study really tried to get a wider swath of individuals to see if CGM helps.

To get into the trial, patients had to be on one or two daily injections of long- or intermediate-acting basal insulin without prandial insulin, and they could be on any other glucose-lowering medications. The A1c to get into the study started out at > 8% and then was lowered a little bit to > 7.8%. But in the end, the average A1c was around 9.2%.

Another point that was really important is that all of these patients had to be followed by a primary care provider. We, the investigators, did not make the insulin dose adjustments. We gave recommendations to primary care providers to make the dose adjustments. We also taught the patients to titrate their insulin to meet fasting targets.

The randomization was 2:1 to CGM vs self-monitoring of blood glucose (SMBG). In the CGM group we had 116 patients vs 59 who were in the traditional SMBG group.

The results showed that those in the CGM group had a fall in their A1c from 9.1% to 8% over the 8 months of the trial. Those in the SMBG group had a fall in their A1c from 9% to 8.4%. This 0.4% reduction in A1c is statistically significant. I really think that CGM helped us improve A1c in the patients in the trial. But there are a number of caveats that I want to introduce, and they're based on my own experience.

Education Needed for Both Patients and Health Professionals

First of all, at my center, my patients didn't have access to a diabetes educator in their real life. I think that just having them see our study coordinators who helped explain diabetes management to them and what they should be doing was really helpful, because their A1c got better in the fingerstick group. I think that was because of the staff who helped them.

The other issue was that I didn't get to make the insulin dose adjustments myself; I made recommendations to the primary care providers. In some cases, the primary care providers did exactly what I said, but in other cases, they didn't. I think it's because the primary care providers weren't yet used to continuous glucose monitoring and how it could help their patients.

I think this trial showed the benefit of CGM in people with type 2 diabetes on basal insulin, and I think that we could enhance the outcomes further, both by providing patients with ongoing education and support, and helping train primary care providers to understand CGM and utilize it in their own practices.

This was a very interesting study. It taught me a lot. We have a lot to do in terms of educating both patients and providers about using CGM. But this is a good start. Frankly, I think CGM should be used in all our patients who are on insulin in any sort of regimen because it helps improve their outcomes.

Anne L. Peters, MD, is a professor of medicine at the University of Southern California (USC) Keck School of Medicine and director of the USC clinical diabetes programs. She has published more than 200 articles, reviews, and abstracts, and three books, on diabetes, and has been an investigator for more than 40 research studies. She has spoken internationally at over 400 programs and serves on many committees of several professional organizations.

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