Stepwise Approach to Continuous Glucose Monitoring Interpretation for Internists and Family Physicians

Marked pregnancy-induced insulin resistance may require that patient receive high-dose large-volume insulin injections. However, these types of injections may reduce the therapeutic effectiveness of the insulin.

In this episode of the Better Edge podcast, Grazia Aleppo, MD, and Emily D. Szmuilowicz, MD, discuss their recent research published in Postgraduate Medicine. Their research proposes a new treatment regimen for pregnancy-induced insulin resistance that is guided by continuous glucose monitoring (CGM). This aims to give internists and family medicine physicians a simplified and consistent approach to CGM interpretation that can be easily implemented in a brief office visit.
Stepwise Approach to Continuous Glucose Monitoring Interpretation for Internists and Family Physicians
Featured Speakers:
Grazia Aleppo, MD | Emily Szmuilowicz, MD
Grazia Aleppo, MD is a primary clinical interest is Diabetes, especially Diabetes and Technology and the application of the use of Insulin pump Therapy and real Time Continuous glucose monitoring sensor therapy to Diabetes type 1 and Diabetes type 2. 

Learn more about Grazia Aleppo, MD 

Emily Szmuilowicz, MD is Program Director, Endocrinology Fellowship, Northwestern University Feinberg School of Medicine. 

Learn more about Emily Szmuilowicz, MD
Stepwise Approach to Continuous Glucose Monitoring Interpretation for Internists and Family Physicians

Melanie Cole (Host): Continuous glucose monitoring use has expanded rapidly in recent years among people with both type 1 and type 2 diabetes. As we see an increasing prevalence of type 2, many of whom receive their diabetes care from internists and family physicians rather than specialists, it's becoming increasingly incumbent upon physicians within internal medicine and family practice to interpret and utilize CGM data in real world clinical practice.

Welcome to Better Edge, a Northwestern Medicine Podcast for physicians. I'm Melanie Cole. And joining me in this thought leader conversation panel today is Dr. Grazia Aleppo, she's a Professor of Endocrinology in the Department of Medicine at Northwestern Medicine, and Dr. Emily Szmuilowicz, she's an Associate Professor of Endocrinology in the Department of Medicine at Northwestern Medicine.

Doctors, thank you so much for joining us today. And Dr. Szmuilowicz, there's an increasing prevalence of type 2 diabetes as I just said in my intro. How can new technologies like continuous glucose monitoring or CGM play a role in helping patients to manage diabetes? How much do healthcare providers rely on this type of provided data when it comes to managing diabetes? Tell us a little bit about that and the role of CGM in diabetes management.

Dr Emily Szmuilowicz: Thanks so much for having us. And yeah, as you mentioned, CGM use is expanding so rapidly and growing by the day, and we think this is such an incredible change that's evolving in our current time in the course of management of type 2 and type 1 diabetes.

There's so many different ways that CGM can help our patients and our providers. I think it falls into really a few categories of the ways in which it helps us. One is just that it gives us so much more information, instead of getting a few snapshots of glucose levels over the day, typically three or four levels over the course of the whole day. In the current systems, we're getting readings every five to fifteen minutes, which gives us hundreds and then thousands of readings over the course of days to weeks and months. The analogy I like to use with patients is if you wanted to see what a movie was about, would you watch the first five minutes, the middle five minutes and the last five minutes, or would you just watch the movie from start to finish?

And when you describe the differences between traditional sort of what we call fingerstick monitoring, how that compares with a fuller picture like continuous glucose monitoring where we get multiple levels every few minutes throughout the day. It starts to become clear how much more information we get about patterns. Not only levels, but patterns, meaning where is the glucose levels starting, where is it coming from, what's the direction, what are the factors that lead to an increase or decrease, as opposed to just where is it in that particular moment.

And I think a couple other just really important benefits that are worth mentioning are, one, the safety benefits for people who take insulin primarily. We all know that while insulin is a life-saving treatment and the foundation of care for many people with diabetes of type 1 or type 2, the main risk of it is low glucose. And for many years, we've been limited in our ability to detect low glucose, for example, overnight or when people are not checking. And our patients are now empowered with the ability to know that, if they have a low glucose level, they'll be woken up and they can treat it and they can make medication change adjustments to prevent it from happening in the future.

And I think the third really big role for CGM, and this applies to people with all forms of diabetes, is that CGM gives our patients the ability to see themselves, the trends that are happening in their glucose levels over the day and relate them to lifestyle modifications, meal choices, changes in physical activity, and really have a coach of sorts that lives with them in a way that no family member and no doctor could ever serve, meaning having real-time feedback of not only bad things, not only saying, "Well, this high carb meal, look how high it made your glucose." I think a lot of patients think that they're only going to get negative feedback from a monitor like this. But I think a lot of our patients are surprised at how much positive feedback they get from a device like this and how much encouragement they get, that when they add a little bit of protein to their meal or they go for a walk after dinner or they make one just very small change in what they're doing, timing of medication, for example, they see in real-time the benefits. And I think it's very encouraging and empowering to patients in a way that we don't have any other ability to do.

Melanie Cole (Host): What an exciting time to be in your field, doctors. Wow. That was an excellent explanation and so comprehensive. So, Dr. Aleppo, briefly describe some of the available CGM systems that are out there today and speak a little bit about patient selection because there's this diverse group of potential candidates who could benefit from CGM use. Speak a little bit about the different systems available today.

Dr Grazio Aleppo: For sure. So there are two different categories of personal CGM, the one that is disposable. And within that, there is another subcategory of real-time versus intermittent scanning. The difference is that the real-time gives you data on a smart device or a reader throughout the day, and the intermittent scanning needs to be scanned into the sensor transmitter unit to retrieve the data. And if you don't do that often enough, you will have a lag of information, so a pause, you don't know what the glucose are doing, so you need to scan pretty often. The other one is an implantable sensor that is available in the states up to 180 days with a small procedure, gets inserted and removed every six months from one arm to the other.

Now, we have an important category, which is the professional CGM. And why is that important? It's very important, especially for primary care. When patients don't have the chance to use these sensors through the insurance, then they can do this procedure, which are covered by insurance, even the government insurance. And so the professional CGM allows the provider to do either a blinded, so masked, no data visible to the patient throughout those 10 or 14 days or unblinded, so the patients can see the data in those 10 days. And with some instruction, they can do so well. And so, the primary care or any provider can use this in their practice, their practice owned, and they retrieve the data and review with the patient. That it's a very, very powerful information. The aha moments are so many, the patient usually end up wanting to use these things and never give it back and use it all the time. And so these are the two kinds.

As far as patient selection, if I could say everybody should have one, I would be considered a bit, you know, insane. But no, that's my view because, in fact, every patient who goes on a sensor, whether it is professional for those 10 or 14 days or use it personally. And especially type 2 patients, they recover so much information from the sensor and they really are astounded by how much better they can do when they walk 10 to 15 minutes after dinner that I keep saying them to do, and say, "Oh, you're right." Not that I'm right, this is happening to everybody. You eat your meal and you just walk it off and, miraculously, those glucose are not so high overnight or the next day. Or you know, don't choose the bagel, look at, you know, the high fiber food or the eggs or something other than just cereal. And that makes a huge difference. So we play with patients and so we talk about the real things of life, not the abstract or the scary things, like complications. We keep it simple and the patients who actually I invited to use CGM, whether professional, you know, for two weeks, every so many months or one week or, you know, for good, personal, they really get so much out of it that is beyond "I am the doctor or the patient." The patient becomes their own providers as Emily was saying before. And so it becomes so empowering. It's a great behavior modifier, but also it's truly giving patients a lot of really power to do better for themselves if they do it.

Melanie Cole (Host): Wow. Isn't this so interesting? And Dr. Aleppo, sticking with you for just a minute, what are some of the barriers to the use of CGM and some of the common mistypes to reading the CGM data? Are there risks to patients? What have you seen are some of the challenges that both providers and the patients themselves have had to overcome?

Dr Grazio Aleppo: I always bring you back to education and training. This is a great tool. But if you think about some people who get classes to learn their phone, why wouldn't they get a class to learn the CGM? And that applies to both patients and providers. Number one, if you don't know how something works, you'll feel afraid of it, then you don't use it well.

For the patients particularly, yes, it is a very simple tool to use, but it's still a medical tool. And so when you guide the patient how to use it best and overcome those, you know, troubleshooting where sometimes the alarm doesn't work, it works too much, it wakes me up in the middle of the night, and explain to them how to work with those systems and tools, you can empower the patient to just understand the tools that are thrown out of the window like a Frisbee, okay? So that's one.

For the provider, the provider needs to recognize this is not, you know, sort of a mysterious tool. They're very simple to read. And as long as you have a very structured way to do it in a step-wise approach that Emily will talk about in a minute, it's very simple to approach. Some mistypes could be that people don't realize that there are many types of hyperglycemia.

For example, I'd give you an example. They see that glucose levels are high, the impetus would be to change an insulin dose. But actually, you need to see is the glucose high because it was low before it got high? So that is what the practitioner is to really pay attention to and say what causes the high. So you can see whether the patient has a low glucose before then, you know, for glucose for-- I wish it was just for glucose-- but drank a gallon of juice. So they overtreated the low glucose because they're afraid they're going to die because they feel so sick from hypoglycemia. And then, they have blood glucose or sensor glucose of 250. The issue is why did they go low? And so if you can guide the provider to do a very simple approach to see what the issue really is, and not to be superficial and digging a bit more, that will be very easy to overcome in terms of concern. And there will be no concerns as far as errors in terms of how to adjust the therapy, even in a very short visit, like primary care would be. It's all doable as long as you teach the provider how to read it.

Melanie Cole (Host): Such important points. And Dr. Szmuilowicz, you have both published a paper about interpreting this data from CGM devices. Tell us a little bit more about the paper and why you both developed this approach for CGM monitoring.

Dr Emily Szmuilowicz: I think that the answer to that piggybacks very nicely off of what Grazia just said, which is that CGM can be overwhelming, right? As any test can be. I remember thinking back to the way I felt when I looked at my first EKG, when I was a medical student or a resident. There's just a lot of data there. And I remember when someone sat down with me and said, "No, you just need to approach this systematically. You need to look at rate first, rhythm, et cetera, et cetera." It's the same thing when you're looking at a report from a continuous glucose monitor. We want to encourage providers to not be overwhelmed by the large amount of data that you can find on all the computer programs that display the data and to focus instead on a systematic approach, looking at the forest first and then the trees.

I think that's a very important guiding principle. If you just dig into the data, you're going to get lost. You have to start with sort of the 30-foot view and look back and say, "What are the major issues?" And we give in our paper practitioners a systematized way of doing that. Looking first at glucose metrics. First identifying what is the problem. Is it hyperglycemia, hypoglycemia or both? And I'll come back to that in a second just to piggyback on what you said, Grazia.

The second question is then where is the problem? And we use the pictorial display, something called an ambulatory glucose profile, which is a standardized way of displaying the data visually. And we show our readers how to find that information in that pictorial display. And then, the third step is how do you modify treatment? I think we all have a tendency to jump to the how first. You really can't adjust therapy until you first identify what the problems are.

And I was going to say the exact same thing. I guess great minds think alike, but I was going to say the exact same thing about what are the most common mistypes or mistakes in looking at CGM. And I think the biggest mistake that I see is going straight to hyperglycemia, which is usually the thing that the patient is most concerned about and often the doctors are most concerned about. But like Grazia just said, you could have 10 minutes of hypoglycemia in your day that leads to what we call defensive eating, meaning eating to correct a low glucose or, for example, if you're low before a meal, you can't take the medicine that you're supposed to be taking with your meal and so the glucose level then becomes high for five or six hours or even more as a result of that 10-minute episode of hypoglycemia.

So in our systematic approach, we encourage our CGM interpretation team to force yourself to look for hypoglycemia first, even though it's not where your brain goes first. Identify that, treat that first, and then treat the hyperglycemia later. And I find that in my own practice, when I have started to force myself to do that, it has really shaped and improved the way I approach CGM interpretation, and we'd like to impart that systematic approach to internists alike because really it's the same principles that apply when an internist or an endocrinologist or anybody is approaching this data.

Dr Grazio Aleppo: But also if I can interject also, show the patient their accomplishment. So always look at the glucometrics instead of the patient. Look how close you are to target. You are doing better, even by 10 to 15%, something we call time and range, because actually even 5% is clinically significant. So tell the patient they're doing great because they are. They're wearing the sensor. They're looking at the sensor. You can see that there is a change, even if it's small. It doesn't have to be, you know, 25%, that's really high. But just take a look how much better they were doing from the previous time and encourage them. Then, you say, "Okay, there are trouble spots. What can we do?" They'll tell you what the trouble spots are. So they're very candid. They know because they see before we see that, right, Emily? So I think that that is also very important to just tell the patient, "This is how good you're doing. You're this close to, let's say, 70%, which should be the target for time and range spent between 70 and 180 milligram per deciliter." Emily?

Dr Emily Szmuilowicz: And I'm going to piggyback on that again, just to go back to you. I couldn't agree more. And the nice thing also is that patients, they have these apps on their phone. They can follow along with you, right? So if we're looking at things like the metric that Grazia just mentioned, time and range, the patient can see that and how it changes every couple weeks in between the visit, which is very different than the old model, which was that patients would live in sort of fear and blindness between visits and they'd say, "What is my A1C going to be when I go to the doctor's office?" That leads to a lot of stress, anxiety, feeling like they may be judged when they show up at the visit. When they wear a device like this, they see it all the time. They don't need to wait for a doctor to interpret. Of course, we guide them and we help them and we look at it together with them. But they don't need to wait for that visit to know what's happening in their own lives. And I think that's the way it should be. The patient should have the power to see what's going on in real-time, not wait for those every three-month visits.

Melanie Cole (Host): You both absolutely just answered my next question, and thank you for explaining those key factors involved in achieving that successful outcome with CGM because it really is about education for both the provider and the patient. You both explained it so well. Dr. Szmuilowicz, how can internists and physicians put these tools into practice because you've spoken about education, educating both providers and the patients. But I think one of the most important messages from this great podcast today is exactly this question. How can they put these tools into practice, and what would you like them to know as the experts that you both are?

Dr Emily Szmuilowicz: Thank you for asking that. And I think that one thing I just want to acknowledge is that we understand how busy internal medicine visits are. We appreciate that we are focusing on one or two of the many, many things that an internist or family physician is focusing on over the span of a very short visit. And we appreciate how hard it is. And by the approach that we're suggesting, we think that it's doable to accomplish this in a short time.

I think that the key principle that I would encourage any physician to do, endocrinologist, internist or whomever, is to take a little bit of time at the beginning to read a paper like ours or another one, but it's some kind of a systematic approach and force yourself to go through the steps. I think it's very similar to what we hear about, for example, coaching sports. We always say, you know, if you want to learn how to hit a tennis ball or you want to learn how to pitch a ball in baseball, everyone says, "Focus on your form first. Don't aim," right? Get the muscle memory, figure out what the steps are and the aim will come as you get better at doing that.

And I think one of the mistakes that we make is trying to aim right from the beginning. We tell our trainees the same thing. You have to force yourself to go through the steps the same way we've all learned how to read EKGs, the same way we learned to do a lot of things in medicine. We learn the steps and then, with time and practice, in a very short time, I think you can start to really start to glean meaningful data from these devices that our patients are wearing, instead of the data disappearing off into nowhere and nobody looking at it, which I think is what's happening a lot of the time.

Melanie Cole (Host): And so Dr. Aleppo, now that Dr. Szmuilowicz spoke about how internists and physicians can put these tools into practice, how have you worked with your internists and family medicine colleagues at Northwestern Medicine? And after you tell us that Dr. Szmuilowicz, you add in because, as I understand it, you're both from different regions.

Dr Grazio Aleppo: Yes. So we start with research actually. So there was this wonderful trial called the Mobile Trial, which was done with primary care patients who could not see the endocrinologist to be able to be enrolled in this study. And then, we put them on a CGM or versus PGM. And then, we follow them for up to 14 months. And the beautiful thing was that at the end, those had to just be hands off. And so, our colleagues with whom I work with in that particular trial got really familiar because they would receive every other week these reports with the information and the interpretation. So they really got to like it a lot. And so when this was over, we started to do this with them in practice.

So we have, for example, something called the HSC, which is our health system collaborative where we try to implement this day by day and we have more and more physicians prescribing these CGMs. And then, we also have some help with pharmacy, and Emily will talk about that more in detail. But for us, we like to have patients either do this professional CGM, which we can interpret for them and send them back the patients through something called the Tune-Up Pathway which is another program we have here in Northwestern Medicine and that receives the data. And then, they continue with their patients using these systems and are familiar because there's something to base it off, like my interpretation initially, and they continue to use it or try to implement more and more CGM in primary care by just giving this very simple one, two, three steps of the what, the where, and the how and so they become more familiar. But Emily has a very nice pilot going on in the north region. Emily?

Dr Emily Szmuilowicz: Thanks, Grazia. Yeah. Grazia and I worked together in the central region. And in addition, I spent some time of my week working in the north region and so we've been working together with primary care doctors there to try and roll out exactly this, a systematic approach to CGM interpretation amongst our colleagues in the internal medicine field. And it's very exciting. And with the help of systematic approaches like the one that we just published, we're hoping to really show that this type of activity can lead to improvement in patient outcomes as well.

And I'll mention one other thing, which is that we're also working hard. Grazia and I work very closely, of course, with the fellows here, the trainees in the endocrine department here at Northwestern. And one other really important avenue that we're hoping to take is also training internal medicine trainees, because I think one of the barriers to using this type of technology in primary care and internal medicine is that people weren't trained in how to use it. And so, we're hoping to actually scroll back years in training. And instead of waiting until people get into practice to treat them, to really make this one of the foundational skills that they gain as part of training. And that's another avenue that we're taking in the central region.

Dr Grazio Aleppo: And medicine is an ever evolving sort of system and a field. So when we were residents a long time ago, something didn't exist. And so we had to learn new things and that was part of our training from internship to resident to fellowship, and even in practice. So now, we have these phenomenal tools that really are helping patients with A1c reduction, hypoglycemia reduction, weight loss, you name it, even complications. There is some data that's coming up that shows that there's some reduction in complication rates. So, why not have these young people learning in the cradle, as I say all the time, so they will be something second nature. They don't have to be facing these challenges and maybe from a practitioner or colleagues in practice for a while might be facing because this is something a bit newer to them.

Melanie Cole (Host): Dr. Szmuilowicz, last question to you. Can you leave us with one parting piece of information for physicians who are listening? Really, this is about combating the shortage of endocrinologists so that providers in internal medicine and family medicine can best treat their patients.

Dr Emily Szmuilowicz: It's an important question. I think that, as you said, the prevalence of type 2 diabetes is so high as is well known, that the majority of people with type 2 diabetes, for example, are going to be seen by an internist instead of an endocrinologist. And so our hope is that by giving internal medicine physicians the tools to use this as an effective technology, that we can allow people with type 2 diabetes to benefit from these technologies in the same way as folks who see endocrinologists. And I think my parting words would be to not be overwhelmed by this technology, the same way we all feel overwhelmed, like Grazia was just saying when we encounter something new that we've not been trained in. Our hope is that by putting together an approach like this, that this type of technology will no longer be overwhelming, but rather something that internists will embrace and use it not only to improve their care for people with type 2 diabetes, but also to really allow people, most importantly, people with type 2 diabetes to become empowered by this information.

Melanie Cole (Host): Thank you both so much for joining us today. What a great podcast this was. And to refer your patient or for more information, please visit our website at to get connected with one of our providers. That concludes this episode of Better Edge, a Northwestern Medicine Podcast for physicians. I'm Melanie Cole.