TOPLINE:

The prescription of metformin was associated neither with the development of age-related macular degeneration (AMD) in participants without the condition nor with progression to advanced forms of the eye disorder, even after up to 10 years of follow-up.

METHODOLOGY:

• Investigators conducted a retrospective cohort study using electronic health records to examine whether the prescription of metformin was linked to the development or progression of nonexudative AMD.
• They included participants aged 65 years or older who had at least one eye care visit and 6 months of health records.
• Participants prescribed metformin included 189,725 without AMD (mean age, 75.9 years; 53.7% women) and 9244 with mild or moderate nonexudative AMD (mean age, 80.5 years; 56.9% women); each group was propensity score-matched with an equal number of those not prescribed metformin.
• Outcomes were the development of new AMD in those without the condition and progression to geographic atrophy or neovascular AMD in those with mild or moderate nonexudative AMD, assessed at 5 and 10 years and overall.

TAKEAWAY:

• In participants without AMD, the risk of developing the condition was similar, whether or not they were prescribed metformin; the risk remained similar at both 5 and 10 years.
• Among participants with mild or moderate nonexudative AMD, the risk of progressing to advanced forms of the condition was similar between those with and without the prescription of metformin at both 5 and 10 years.

IN PRACTICE:

"The results of our analysis do not support a protective effect of metformin against the development of AMD or its progression to geographic atrophy or neovascular AMD," the investigators reported.

“Despite growing interest in metformin’s anti-inflammatory and anti-aging properties, it is critical to recognize that metformin is not without risk,” experts wrote in an invited commentary accompanying the journal article. “It can cause gastrointestinal side effects, vitamin B₁₂ deficiency with long-term use, and, in rare cases, lactic acidosis, particularly in individuals with kidney impairment. Until high-quality causal evidence is available, the totality of the currently available evidence does not support the consideration of clinicians to prescribe metformin for the sole purpose of preventing AMD or slowing its progression."

SOURCE:

This study was led by Darren A. Jindal, PhD, of Case Western Reserve University School of Medicine in Cleveland. It was published online on September 18 in JAMA Ophthalmology.

LIMITATIONS: 

The findings from this retrospective study represented associations, not cause and effect. The use of any other medications for diabetes was not accounted for in those prescribed metformin. Information on dosing and whether the participants used the prescription was unavailable.

DISCLOSURES:

This study received support from multiple sources, including the National Institutes of Health, Research to Prevent Blindness Challenge Grant, Cleveland Eye Bank Foundation, and the Clinical and Translational Science Collaborative of Northern Ohio. Several authors reported receiving personal fees, research fees, grants, and/or consulting fees from various pharmaceutical, eyecare, and other companies, including Alcon, Iveric Bio, and Bausch + Lomb.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.