Metformin Linked to Slower Progression of Age-Related Macular Degeneration

Research indicates that metformin, a common diabetes medication, is associated with a slower progression of age-related macular degeneration (AMD), a leading cause of blindness in Western countries.

Individuals with diabetes aged 55 and older who were taking metformin demonstrated a 37% lower likelihood of developing the intermediate stage of AMD over five years, in comparison to those not using the medication.

Understanding Age-Related Macular Degeneration (AMD)

AMD impacts the central retina (macula) and can result in the loss of light-sensitive tissue (known as geographic atrophy, or 'dry' AMD) or damage from abnormal blood vessel growth ('wet' AMD).

Intermediate and advanced AMD affects a significant portion of the population, impacting 10-15% of people over 65. This includes an estimated 1.1 to 1.8 million individuals in the UK, where it stands as the primary cause of blindness in high-income nations.

The estimated annual cost of AMD in the UK is a substantial £11.1 billion. Currently, geographic atrophy lacks treatment in the UK and Europe. Existing treatments for wet AMD are costly and involve repeated intraocular injections.

The Study: Methodology and Results

This research, conducted by the University of Liverpool, involved analyzing eye photographs from 2,000 participants. These participants were part of a five-year routine diabetic eye disease screening program in Liverpool.

Researchers carefully evaluated the presence and severity of AMD in the photographs, comparing individuals taking metformin to those not taking it. Adjustments were made for potential biasing factors such as age, sex, and duration of diabetes.

The study found a clear association: the odds ratio for developing intermediate AMD over five years in the metformin group was 0.63, with a 95% confidence interval of 0.43 to 0.92.

Prior to this study, a potential benefit of metformin in AMD was hypothesized. This research marks the first instance of AMD grading directly from eye photographs, an advancement over previous studies that relied on secondary data like GP diagnostic codes or insurance claims.

Implications for Future Treatment

Dr. Nick Beare, the research lead, highlighted the current lack of treatment options for many individuals with AMD. He stated that this finding represents a significant step in identifying new treatments.

Dr. Beare proposed that metformin should be tested as an AMD treatment in a clinical trial, citing its potential to preserve vision for many.

The research paper was published in BMJ Open Ophthalmology.