Use of CGM linked to lower risk of retinopathy in type 1 diabetes

Key Takeaways

  • In patients with type 1 diabetes, use of continuous glucose monitoring (CGM) devices was associated with lower odds of developing diabetic retinopathy, according to a study.
  • The authors suggest the positive effect may be driven by more time spent within a certain blood sugar range.  

In patients with type 1 diabetes, use of CGM devices that continuously monitor blood sugar — alone or with insulin pumps — was associated with lower odds of developing diabetic retinopathy and proliferative diabetic retinopathy, the more severe form of diabetic retinopathy, compared with no use, according to a retrospective cohort study published by Risa M. Wolf, MD, of Johns Hopkins University School of Medicine in Baltimore, and colleagues in JAMA Network Open.  While insulin pump use alone was not linked to diabetic retinopathy risk, CGM and pump use together were associated with lower odds of developing proliferative diabetic retinopathy compared with no CGM or insulin pump use, the researchers reported. 

The positive effect likely isn’t entirely produced by glycemic (blood sugar) control via CGM since the researchers controlled for HbA1c, a measure of average blood sugar, co-author Nestoras Mathioudakis, MD, MHS, also of Johns Hopkins University School of Medicine, told MedPage Today. Instead, “this is probably being driven by glycemic variability and the percentage of time that you’re staying within a certain [blood sugar] range.”

It’s not clear why use of insulin pumps alone was not tied to signs of improvement in diabetic retinopathy. However, Mathioudakis said the study’s sample size may have been too limited to accurately reflect their impact. He also noted that the current state of the art is a hybrid, closed-loop CGM-insulin pump device that automatically produces tighter glucose control. It wasn’t available during the 2013-2021 period of the study. “A similar study will need to be done over the next 5 years to really start to look at the impact of people using those newer technologies,” he said.

Could those who used the devices in the study simply be healthier overall or more likely to take care of themselves? Mathioudakis said the researchers tried to control for this possibility by adjusting their analysis for various possible confounders, variables that are associated with both factors being measured in an experiment, and can therefore falsely demonstrate an apparent association when no real association exists. 

Co-author T. Y. Alvin Liu, MD, of Johns Hopkins University School of Medicine, told MedPage Today he urges patients to use the devices, noting that they often ask, “Does that mean these devices could decrease my chance of going blind?” he said. “And the answer is yes. That is a very encouraging message and motivating message for them to go down this path.”

This study received funding from the Research to Prevent Blindness to the University of Wisconsin-Madison Department of Ophthalmology and Visual Sciences, and from the National Eye Institute of the National Institutes of Health.

Source: Randy Dotinga, MedPage Today, March 8, 2024; see source article