Use of Diabetes Technologies and the Development of Diabetic Retinopathy in Patients With Type 1 Diabetes
In this video, Risa M. Wolf, MD, speaks about her team's study that examined the use of diabetes technologies—continuous glucose monitors (CGMs) and insulin pumps—and whether that was associated with the development of diabetic retinopathy in patients with type 1 diabetes. Dr Wolf discusses how the use of CGMs in patients with type 1 diabetes was associated with a lower odds of developing diabetic retinopathy, the benefits of physicians incorporating CGM in the management of patients with diabetes, and what future research can be done on this topic.
Additional Resource:
Liu TYA, Shpigel J, Khan F, et al. Use of diabetes technologies and retinopathy in adults with type 1 diabetes. Jama Netw Open. Published on March 6, 2024. doi:10.1001/jamanetworkopen.2024.0728
Risa M. Wolf, MD, is a pediatric endocrinologist and associate professor of pediatrics at The Johns Hopkins Hospital/Johns Hopkins Children's Center (Baltimore, MD).
TRANSCRIPTION:
Risa M. Wolf, MD: My name is Risa Wolf. I'm a pediatric endocrinologist at The Johns Hopkins School of Medicine. I am the director of the pediatric diabetes program here.
Consultant360: Can you please give us an overview of your research article titled, “Use of Diabetes Technologies and Retinopathy in Adults With Type 1 Diabetes?”
Dr Wolf: One of my very big interest areas is diabetic retinopathy and how we can essentially prevent it as a pediatric endocrinologist. This is something that I really focus on in my clinical practice as well as research as diabetic retinopathy is a major complication of diabetes and can lead to vision loss and blindness. Particularly, in the young adult working-age cohort of individuals. So, the question that we wanted to address here is, in this new age of diabetes technologies, is there any protection or benefit in preventing diabetic retinopathy from use of continuous glucose monitors or CGMs and insulin pumps and whether that is associated with the development of diabetic retinopathy?
C360: How did this research topic come about?
Dr Wolf: So, we have done a lot of work in the diabetic retinopathy space in the pediatric population. And one study that we did in conjunction with our colleagues at Texas Children's Hospital was looking at the use of insulin pumps and whether that was associated with development of diabetic retinopathy in the pediatric adolescent population. And we found that youth who use insulin pumps had a lower likelihood of developing diabetic retinopathy later. So, we wanted to look at this in the adult population and as a very large diabetes program here at Johns Hopkins, both pediatric and adult, we had a really large cohort of adults with type 1 diabetes with very well described data and in conjunction with our adult endocrinology colleagues as well as our Wilmer ophthalmology colleagues. And that includes Dr Alvin Liu, who's the first author on this manuscript, and my colleague Dr Nes Mathioudakis, one of the other senior authors, we have this very well described cohort of adults with type 1.
And then we were also able to obtain very specific ophthalmology reports as well as review their images to see if there was diabetic retinopathy. And what we really wanted to do here was take a cohort of adults who at initiation into this study period, which lasted a bit, was an eight year study period to look at patients who did not have baseline diabetic retinopathy and were either using a CGM at that time or we're going to start using one during this period. And then to see whether there was any association with development of diabetic retinopathy.
And we also looked at this with insulin pump use because this was a very well described population and we knew what their CGM use was, and if they started it during the study period, we even knew their start date. And the same thing with the insulin pump use. So having the ability to do this and to look over time was really a unique opportunity. And then the other piece of this was that diabetic retinopathy, in terms of their progression and development, was very well described about two to three decades ago in terms of what the progression looks like. But that was all before the age of diabetes technologies. And in the last 10 to 20 years we've really seen an explosion of use of these technologies and we really wanted to understand how use of these new technologies may be associated or affect diabetic retinopathy. And that's how this came about.
C360: Can you elaborate on the results of your study and did those findings surprise you?
Dr Wolf: So, in this study we had a large cohort initially and, based on making sure that the patients had no diabetic retinopathy at baseline, that led us to exclude some patients who had baseline had diabetic retinopathy and also patients who may have started using CGM after developing diabetic retinopathy. And there you can say, "well maybe if they start to have complications they would be more inclined to use a CGM or an insulin pump." So we wanted to make sure that this was a really clean sample. So we started with the group of patients, it ended up being 550 with type 1 diabetes who started out at baseline with no diabetic retinopathy and were either using a CGM at the start or started to use one during the time of this study. Most of the patients had a diabetes duration close to 20 years and the average A1C at starting was 7.8% In this cohort, 62% were using CGM, 58% were using an insulin pump, and 47.5% were using both. During the entire study period of 8 years, 44% or 244 of that 550, had some form of diabetic retinopathy at some point during this study.
So, on our initial analysis, what we found was that CGM use was associated with a lower odds of diabetic retinopathy as well as proliferative diabetic retinopathy. And CGM with pump together was associated with a lower odds of proliferative diabetic retinopathy compared with no CGM use at all. What I think we found interesting in these results was that insulin pump alone was not associated with a lower odds of developing diabetic retinopathy. And this was in contrast to the study that we did in adolescents and is also in contrast to a study of pregnant individuals that was studied that showed a lower association with diabetic retinopathy when using an insulin pump. And we thought that potentially this was due to the fact that our cohort had a much longer duration of diabetes, which is a big risk factor for diabetic retinopathy. So that was one of the things that we potentially found surprising.
And then when we did a multi-variable logistic regression, adjusting for age, sex, race, ethnicity, diabetes duration, and presence of other microvascular and macrovascular complications, as well as insurance type and A1C, we still found that CGM use was associated with a lower odds of diabetic retinopathy and proliferative diabetic retinopathy compared to patients who did not use CGM. And I think this really spoke to us because really despite all other factors including insurance, and there's definitely literature to suggest that having public insurance might be associated with a higher risk for retinopathy and even controlling for A1C where we know that a higher A1C is associated with retinopathy, we still show that even when controlling for all of these individual variables, CGM was still associated with the lower odds of diabetic retinopathy and proliferative diabetic retinopathy, which to us really suggests that there is some benefit or there is an association with some benefit. It's definitely something that we should all consider in our care of patients with diabetes, particularly because it is standard of care.
C360: In your opinion, how would you like to see these results impact standard practice?
Dr Wolf: Currently, CGM use in type 1 diabetes is considered standard of care and it has been for several years and for insulin pumps for those where you think there will be a benefit and patients can utilize the pumps, it is also recommended per the American Diabetes Association and other diabetes association guidelines. But I think, obviously, there are still people who are not using CGM or maybe not insulin pumps and I think having additional data that suggests that there might be some potential association with a lower risk for diabetes-related complications could help maybe convince some patients to consider using it and encourage physicians and diabetes providers to make sure that they're recommending it to all patients so that we know that everybody has access and everybody has the opportunity to use a CGM, which can potentially improve diabetes-related outcomes. Another interesting piece of this is that while CGM use alone was here we saw was associated, there are additional parameters that are data parameters that are gained from using a CGM.
You can look at a patient's time and range. So how much time of the day a patient is spending with a blood sugar between 70 and 180 mg per deciliter. You can look at the average blood glucose from a CGM and then there's also a measure of variability that you can look at when you are reading CGM data. And right as of now, there really are no studies out there that have been able to look at these specific parameters and how they relate to diabetes outcomes. Although that is definitely the future. And I think this study is just really one of the first to show that CGM use in general in a large diverse cohort of individuals with type 1, there can be an association with lower risk for diabetic retinopathy. It's definitely something that we want to see prescribed and recommended to patients with type 1 in order to try and prevent some of these diabetes-related complications.
C360: How do the results of your study impact the multidisciplinary care of patients with type 1 diabetes?
Dr Wolf: I think similarly we would hope that CGM would be recommended and prescribed for all patients with type 1 diabetes and also to consider use of insulin pumps. And one of the limitations of this study, and we highlighted this, is that this data was collected before the use of these hybrid closed loop pump systems or automated insulin delivery systems. And with those we're seeing improvements in hemoglobin A1C, so lower levels of hemoglobin A1C, we're seeing patients spend greater time in target range for glucose based on their CGM data with less variability in their blood sugars throughout the day. So moving forward with the increasing use of hybrid closed loop or automated insulin delivery systems, we'd love to see how that can also impact glycemic outcomes as well as diabetes-related complications and whether that will also have an impact on improving risk for diabetes-associated complications. And the idea would be that in multidisciplinary care, this would be something that we can talk about with our patients and say, "this has been associated with a lower risk and we would encourage you to consider using it," of course with education on it to try and help prevent those complications and improve glycemic outcomes.
C360: What’s next for research on this topic?
Dr Wolf: So I think the next thing really future directions moving forward from here are the two things I mentioned before. So number one is looking at the association of the use of hybrid closed loop and automated insulin delivery systems and whether that impacts long-term glycemic outcomes as well as risk for diabetes-related complications. And I think the second thing that's in order is to actually, now that we have more granular CGM data from patients, is to actually look at whether some of these CGM parameters are predictive or protective of developing diabetic retinopathy and specifically looking at time and range time above range, time below range, the glycemic variability and to see if that has any relationship or association with diabetic retinopathy, in the future. And that will take more longitudinal studies with prospective data collection.
C360: What are the main take-home messages from your study?
Dr Wolf: So the main message is really that CGM use in adults with type 1 here was associated with the reduced odds of developing diabetic retinopathy and proliferative diabetic retinopathy. And although there's been increase in use of CGM because it is standard of care, there are still disparities and gaps in CGM use amongst the diabetic population. And I think that the benefits conferred by potentially mitigating risks for diabetes-associated complication, further supports use of CGM and diabetes management. And that's really the takeaway is that we really want to see all patients using CGM and improving glycemic outcomes, as well as reducing risk for diabetes-related complications.