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Semaglutide, a glucagon-like peptide-1 receptor agonist, may be associated with increased risk of a rare eye condition, results from a large-scale retrospective study have suggested.
Following anecdotal experience that the weight loss drug may be linked to non-arteritic anterior ischemic optic neuropathy (NAION), researchers in the United States analysed data over six years from more than 16,800 neuro-opthalmology patients from Massachusetts Eye and Ear hospital, Boston, Massachusetts, with no history of NAION.
They used the data to examine whether semaglutide prescriptions were associated with increased risk of NAION in patients with type 2 diabetes mellitus (T2DM), obesity, or who were overweight.
NAION presents as a blurring or dimming of vision and is caused by a blockage in the arteries supplying blood to the optic nerves. The usual incidence of the condition is between 2 and 10 cases per 100,000 people in the United States. There is currently no treatment for the condition and it commonly does not improve.
Semaglutide is available as Ozempic (Novo Nordisk), a lower-dose form used to treat T2DM, and Wegovy (Novo Nordisk), a higher-dose form used in weight management for patients with high body mass indexes.
Reporting in JAMA Ophthalmology on 3 July 2024, the researchers found that, the risk of NAION occurring for the first time over a 36-month time period — known as the cumulative incidence — was 8.9% among patients with T2DM who had been prescribed semaglutide (n=194), compared with 1.8% in 516 patients with T2DM prescribed other antidiabetic medications.
For patients who were overweight or obese and had been prescribed semaglutide (n=316), the cumulative incidence of NAION was 6.7%, compared with 0.8% in the non-semaglutide group (n=618).
The authors said their study was, to their knowledge, the first to report a link between semaglutide and NAION.
However, they added: “The design of our study did not enable query into a causal relationship between the two.
“The best approaches to confirm, refute, or refine our findings would be to conduct a much larger, retrospective, multi-centre population-based cohort study; a prospective, randomised clinical study; or a post-market analysis of all GLP-1 RA drugs.”
Commenting on the study, Graham McGeown, honorary professor of physiology at Queen’s University Belfast, said: “[These results do] suggest an association between semaglutide treatment and one form of sight-threatening optic neuropathy, but this would ideally be tested in larger studies.
“Given the rapid increase in semaglutide use and its possible licensing for a range of problems other than obesity and T2DM, this issue deserves further study, but possible drug side effects always need to be balanced against likely benefits,” he added.
