Department of Research & Evaluation News

People with type 2 diabetes may develop diabetic retinopathy, an eye condition that can lead to vision loss. Now, a study of over 77,000 Kaiser Permanente Southern California members shows that greater severity of diabetic retinopathy is strongly associated with a higher risk of heart attacks, strokes, congestive heart failure, and death from any cause.

“Preventive care is paramount, so we are always trying to find ways to better predict who will run into long-term medical problems,” said the study’s lead author Bobeck Modjtahedi, MD, a clinician investigator with the Department of Research & Evaluation, and a vitreoretinal surgeon at the Kaiser Permanente Baldwin Park Medical Center.

The retina, located at the back of the eye, is the only part of the body where noninvasive imaging can directly visualize blood vessels.

“Our findings suggest that the degree of retinal damage captured during routine imaging could one day be utilized as a marker of future vascular health,” Dr. Modjtahedi said.

Large, diverse study population enables new insights

Recently published in Ophthalmology, the new study builds on earlier research that uncovered associations between diabetic retinopathy and risk of vascular events. However, those studies were too small to explore whether a greater degree of retinal damage correlates to greater risk.

For this retrospective analysis, the researchers probed the electronic health records of 77,376 Kaiser Permanente Southern California patients with type 2 diabetes who had undergone routine imaging to screen for retinal damage.

Compared to patients with no retinopathy detected during screening, those found to have mild retinopathy were more likely to experience heart attacks, strokes, heart failure, or death from any cause within the next 5 years. Those with moderate or severe forms of diabetic retinopathy had an even higher risk of each outcome.

This association persisted even after accounting for socioeconomic factors and traditional cardiovascular and diabetes risk factors.

“It’s really groundbreaking stuff to be able to predict disease in this way,” said Donald Fong, MD, MPH, a co-author on the study, chief of ophthalmology at Baldwin Park Medical Center, and director of the Kaiser Permanente Southern California Eye Monitoring Center. He is also an affiliated researcher with Department of Research & Evaluation.

“The retina is unique in that a single image can reveal vascular damage that has accumulated over many years, so it could help enable a more personalized assessment of a patient’s future risk,” Dr. Fong said.

Building knowledge despite pandemic challenges

The research team is now exploring whether their new findings could help improve existing vascular risk calculators—clinical tools that use information about a patient to estimate their personal risk of future vascular dangers.

Since many people with diabetes already receive routine retinal imaging, it would be relatively easy to begin incorporating their degree of retinal damage into these tools.

“The hope is to boost our ability to match each patient to the specific types of interventions and medications that could reduce their future risks,” Dr. Modjtahedi said. “And it might help us avoid unnecessary treatments for people who are actually pretty low risk.”

This research has unfolded over the course of the COVID-19 pandemic, which posed unprecedented challenges for clinicians. Dr. Modjtahedi credits the Southern California Permanente Medical Group’s Clinician Investigator Program with providing infrastructure and support that helped his team conduct meaningful research in spite of an intensified workload.

“We get pulled in different directions clinically, and we definitely faced delays due to the COVID-19 situation,” Dr. Modjtahedi said, “but we were able to navigate that pretty effectively, thanks to our tremendous team.”

Dr. Modjtahedi is also co-chair of the Kaiser Permanente Center for Ophthalmology Research and Innovation and director of the Electrophysiology and Retinal Degeneration Service for the Southern California Permanente Medical Group.

Other authors on the study are: Jun Wu, MD, MS; Tiffany Q. Luong, MPH; and Wansu Chen, PhD, MS, of the Kaiser Permanente Southern California Department of Research & Evaluation; and Nainesh K. Gandhi, MD, MSE, of the Southern California Permanente Medical Group.

Image taken pre-pandemic.