Metformin use in people with diabetes was associated with significantly lower odds of developing intermediate age-related macular degeneration (AMD) over five years.

Published in BMJ Open Ophthalmology, the population-based retinal imaging study was conducted by researchers at the University of Liverpool and Universitas Gadjah Mada, Indonesia. They analysed colour fundus photographs from 2,089 gradable images obtained from adults aged ≥50 years with diabetes attending routine retinopathy screening.

Intermediate AMD occurred less frequently among metformin users, with multivariable-adjusted odds ratios indicating a 37% lower incidence compared with non-users after controlling for age, sex, diabetic retinopathy status, glycaemic control (HbA1c) and diabetes duration. No significant association was observed for early AMD, any AMD, or progression to late AMD after adjustment, said researchers.

“Given metformin’s anti-ageing therapeutic effects, the reduction in risk is plausible and warrants prospective clinical trials,” said the authors.