Weight loss drugs linked to higher risk of eye damage in diabetic patients

Weight loss drugs could at least double the risk of diabetic patients developing age-related macular degeneration, a large-scale study has found.

Originally developed for diabetes patients, glucagon-like peptide-1 receptor agonist (GLP-1 RA) medicines have transformed how obesity is treated and there is growing evidence of wider health benefits. They help reduce blood sugar levels, slow digestion and reduce appetite.

But a study by Canadian scientists published in Jama Ophthalmology has found that after six months of use GLP-1 RAs are associated with double the risk of older people with diabetes developing neovascular age-related macular degeneration compared with similar patients not taking the drugs.

Academics at the University of Toronto examined medical data for more than 1 million Ontario residents with a diagnosis of diabetes and identified 46,334 patients with an average age of 66 who were prescribed GLP-1 RAs. Nearly all (97.5%) were taking semaglutide, while 2.5% were on lixisenatide.

The study did not exclude any specific brand of drugs, but since Wegovy was only approved in Canada in November 2021, primarily for weight loss, it is likely the bulk of semaglutide users in the study were taking Ozempic, which is prescribed for diabetes.

The study found that those who had been taking semaglutide or lixisenatide for at least six months had twice the risk of developing macular degeneration, compared with similar patients who were not taking the drugs. Patients who had been taking GLP-1 RAs for more than 30 months had more than three times the risk.

Marko Popovic, a co-author of the study and physician in the department of ophthalmology and vision sciences at the University of Toronto, said: “GLP-1 receptor agonists appear to have multiple effects on the eye, and in the case of neovascular age-related macular degeneration, the overall impact may be harmful.

“Based on our data, I would advise exercising particular caution when prescribing GLP-1 RAs to older [diabetic] patients or those with a history of stroke, as both groups were found to have an even higher risk of developing [the condition].”

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Source: The Guardian, 5 June 2025