Popular weight loss and diabetes drugs Ozempic, Wegovy linked to increased risk of blinding eye condition

Patients taking semaglutide for weight management at an higher risk of developing NAION compared to those taking the medication for diabetes
The research found semaglutide medications were significantly more likely to lead to the illness NAION, which leads to a reduction in blood flow to the optic nerve, resulting in sudden vision loss.
The research found semaglutide medications were significantly more likely to lead to the illness NAION, which leads to a reduction in blood flow to the optic nerve, resulting in sudden vision loss.iStock, for representation
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New research suggests a link between popular diabetes and weight loss medications Ozempic and Wegovy and an uncommon eye condition that can lead to blindness. 

The study, published in JAMA Ophthalmology, found that individuals prescribed these drugs, which contain semaglutide as the active ingredient, were significantly more likely to develop non-arteritic anterior ischemic optic neuropathy (NAION). NAION occurs when there is a reduction in blood flow to the optic nerve, resulting in sudden vision loss. The optic nerve is a bundle of over one million nerve fibres that transmit visual signals.

NAION is a rare condition that affects 2-10 people out of every 100,000. It is also the second most common cause of optic nerve blindness, with no effective cure.

Those taking semaglutide for diabetes were four times more likely to develop NAION compared to those not on the medication. For patients taking the drug for weight management, the risk was even higher, at over seven times more likely.

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The research found semaglutide medications were significantly more likely to lead to the illness NAION, which leads to a reduction in blood flow to the optic nerve, resulting in sudden vision loss.

“The use of these drugs has exploded throughout industrialised countries and they have provided very significant benefits in many ways, but future discussions between a patient and their physician should include NAION as a potential risk,” Joseph Rizzo, director of the Neuro-Ophthalmology Service at Mass Eye and Ear at Harvard Medical School and the study’s corresponding author, said in a statement.

Rizzo initiated this study after discovering anecdotal evidence. In late summer 2023, the experts found three patients at their hospital who had been diagnosed with NAION-related vision loss in just one week. All three were found to be on semaglutide, which is sold as Ozempic to treat diabetes and Wegovy for obesity.

Ozempic was approved to treat type 2 diabetes by the United States Food and Drug Administration (FDA) in 2017. It helps lower blood sugar levels by encouraging the body to produce more insulin.

In high doses, these drugs reduce appetite and signal fullness before eating by targeting the brain.

In 2021, the FDA approved Wegovy injection for chronic weight management in adults who are obese or overweight and have at least one weight-related condition, such as high blood pressure, type 2 diabetes, or elevated cholesterol.

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The research found semaglutide medications were significantly more likely to lead to the illness NAION, which leads to a reduction in blood flow to the optic nerve, resulting in sudden vision loss.

So the team began a study by reviewing the patient records of over 17,000 patients treated in the six years since Ozempic was released.

Individuals under the age of 12 were excluded from the study, reducing the total number to 16,827 patients. 710 of the included patients had type 2 diabetes, and 979 were overweight or obese.

Further analysis revealed a higher NAION risk in people taking semaglutide for type 2 diabetes compared to others, with a hazard ratio of 4.35. The hazard ratio determines how frequently a specific event occurs in one group versus another over time.

Similarly, they discovered a higher NAION risk in the group taking semaglutide for weight loss compared to the non-semaglutide cohort, with a hazard ratio of 7.28.

The researchers discovered that diabetes and related comorbidities, such as obesity, did not significantly increase the risk of NAION.

They did, however, point out that being male may increase the risk of NAION in type 2 diabetes patients. Furthermore, overweight or obese people taking semaglutide who also have hyperlipidemia (high levels of lipids in the blood such as cholesterol and triglycerides) may be at a higher risk of developing NAION.

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The research found semaglutide medications were significantly more likely to lead to the illness NAION, which leads to a reduction in blood flow to the optic nerve, resulting in sudden vision loss.

Furthermore, the researchers stated that patients with diabetic retinopathy — a complication of diabetes that causes damage to the blood vessels of the retina, the light-sensitive part of the eye — who received semaglutide may have an increased risk of worsening retinopathy. They also likely had a faster rate of progression in the development of new vessels on the inner surface of the retina, which can endanger vision.

The study only shows an association between semaglutide and the eye condition and does not prove that the former causes the latter.

“Our findings should be viewed as being significant but tentative, as future studies are needed to examine these questions in a much larger and more diverse population,” Rizzo said.

He added that this information should be included in discussions between patients and their doctors, especially if patients have other known optic nerve problems like glaucoma or if there is preexisting significant visual loss from other causes.

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