Patients may be at four to eight times the normal risk of non-arteritic anterior ischaemic optic neuropathy.
People taking GLP-1 receptor agonists for diabetes or weight loss may be at higher risk for an eye condition that can cause irrecoverable vision loss, an observational study suggests.
Non-arteritic anterior ischaemic optic neuropathy is the sudden loss of blood flow in the vessels at the front of an optic nerve, and occurs more often in patients with conditions such as diabetes, high blood pressure, and sleep apnoea. It’s painless but causes permanent blindness.
It’s the second most common form of optic neuropathy, with an annual incidence of between two and 10 cases per 100,000, and a significant cause of blindness in adults. The causes are not well understood, but risk factors include cardiovascular diseases, hypertension, diabetes and having a crowded optic nerve.
The authors of a new study in JAMA Ophthalmology were led by their clinical and anecdotal experience to look for an association between NAION and semaglutide.
The team, from Harvard and Brigham and Women’s Hospital, reviewed the records of patients seen at one Boston neuro-ophthalmology clinic between 2017 and 2023, identified all the patients taking semaglutide for obesity or type 2 diabetes and matched them with patients with those conditions but taking alternative medications.
That yielded a study population of 710 patients with T2DM, 194 of them on semaglutide and 516 not; and 979 patients with obesity, 361 on semaglutide and 618 not.
Among the diabetic group, the incidence of NAION was more than four times higher in patients on semaglutide: 8.9% vs 1.8%.
Among the weight-loss group, the incidence was more than seven times higher: 6.7% vs 0.8%.
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Dr Peter Sumich, president of the Australian Society of Ophthalmologists, said while the findings were at an early stage, it reinforced the importance of risk-to-benefit considerations and only taking medications when there was a serious medical need.
NAION, he said, was a stroke of the optic nerve that was not uncommon, and occurred more commonly in patients with artery diseases and patients with crowded or squashed optic nerves, also known as a small cup-to-disc ratio or a “disc at risk”.
This risk factor was easily detected by an ophthalmologist or optometrist, and such an examination would be a worthwhile precaution before starting on semaglutide or similar.
“And if you’re a trendy or recreational Ozempic user just looking to lose a bit of weight, it’s got to make you think twice about using it,” Dr Sumich said.