Dimitra Skondra, MD: Metformin May Serve as Novel Treatment for AMD

New findings presented at the American Society of Retina Specialists 40th Annual Scientific Meeting suggest metformin may be a novel treatment for age-related macular degeneration (AMD).

Data show metformin use was associated with reduced odds of developing AMD (odds ratio [OR], 0.94 [95% CI, 0.92 - 0.96), with low to moderate doses of metformin showing the greatest potential benefit.

In an interview with HCPLive, Dimitra Skondra, MD, Associate Professor, University of Chicago, discussed where the idea to investigate metformin originated and what was uncovered in the search through literature.

"This came up as initially noticing that many of my patients that are diabetic, they don't have macular degeneration," Skondra said. "And I will start looking at why that would be."

Skondra noted the pathways of actions of metformin in the biology of aging and the pathways of AMD had overlap. In searching the claims database, the investigators were able to see information about the eye, as well as other medical conditions and prescriptions.

“We want to see people that have newly diagnosed macular degeneration and in order to do that, we want to make sure they have at least two eye exams without AMD for the year prior to the new onset of the diagnosis,” Skondra said. “It is compared to the people that never get AMD in the same group if the people on metformin seem to be more protected.”

After matching the cohort and controls, Skondra and colleagues found that patients who took metformin had a decreased odds ratio of developing AMD.

“It seems that the low to moderate doses of metformin have the strongest protective effect, and that was found both in the whole cohort and the diabetic only cohort,” Skondra added.

They additionally found that metformin was protective in patients with diabetes without diabetic retinopathy, but was not protective in the presence of diabetic retinopathy. Other agents, including insulin and sulfonylureas, were protective as well, while other diabetic medications actually increased the risk for AMD.

However, when these medications were taken in combination with metformin, investigators observed the risk was no longer demonstrated.

“So metformin has a protective effect like it came into place when people were taking medications that may increase the risk,” Skondra said.

She noted that more needs to be studied, as well as the need for more data from databases and investigating deeper subtypes of AMD and her group is working at this moment in subtypes like dry AMD and nuances of nAMD.

“Sometimes it may be better if we'll see if we can repurpose the medications,” Skondra concluded. “It is an exciting time in medicine, because it saves a lot of money and time when our patients and the answer may be already there in front of our eyes.