Metformin Shown to Decrease AMD Risk in Diabetes Patients

Yu-Yen Chen, MD, PhD

Age-related macular degeneration (AMD) is one of the leading causes of blindness in Americans over the age of 50 years with approximately 2.1 million individuals affected across the nation.

While investigators do not completely understand the way in which AMD develops, previous research, including the drusen formation, which has been shown to be linked to localized inflammatory response, has demonstrated that oxidative stress and inflammation play a key role in both development and progression of AMD. Similarly, both of these factors also play a role in the development of diabetes.

These facts led investigators from Taiwan to examine whether or not the anti-inflammatory and anti-oxidative effects of metformin, a medicine commonly used to treat type 2 diabetes can simultaneously protect against AMD while also controlling diabetes.

The investigative team observed patients recently diagnosed with type 2 diabetes and found that use of metformin resulted in a significantly lower risk of developing AMD.

“Our study is the first to reveal the protective effect of metformin on the development of AMD,” Yu-Yen Chen, MD, PhD, of the Taichung Veterans General Hospital in Taiwan and lead investigator of the study, said in a statement. The findings of the investigation were presented today, October 28, 2018, in an original paper presentation session by Dr. Chen at the American Academy of Ophthalmology Annual Meeting in Chicago Illinois.

The investigators collected information about patients diagnosed with type 2 diabetes between January 2—1 through December 2013 from the Taiwan National Health Insurance Research Database. From there the patients were split into 2 groups: those who took metformin (45,524 patients) and those who did not (22,681).

After following both groups for 13 years, the investigators observed that patients in the metformin group had a lower risk of developing AMD and half as many patients in the metformin group had AMD compared to the control group.

At baseline, the patients in the metformin treatment group had more prevalence of systemic comorbidities. After adjustment for age, gender, and these comorbidities, Cox regression showed a significantly lower risk of AMD development in the metformin group than in the comparison group (HR = 0.53; 0.49-0.58).

According to the investigators, this study has indicated that use of metformin can protect against the future development of AMD, but further research is still needed to understand more. Future studies should focus on determining what mechanism of action of metformin decreases the risk of developing AMD in type 2 diabetic patients who are taking the medication.