Harvard researchers link this to an increased risk of blindness
On this subject, a study that was just published in JAMA Ophthalmology Links Semaglutide to Potential Blindness.
Semaglutide is the active ingredient in the popular drug Ozempic, intended to combat type 2 diabetes, and Vegovi, indicated for weight loss in people with a high body mass index.
The study retrospectively analyzed a total of 16,827 patients who visited the Harvard-affiliated Massachusetts Eye and Ear Infirmary between 2017 and 2023 for neuro-ophthalmologic evaluation.
Of these, 710 had type 2 diabetes. In this subgroup, there were 194 people who were prescribed semaglutide to treat this disease. The rest had diabetes controlled with other drugs.
Researchers led by Ximena Tatiana Hathaway of the Harvard T.H. Chan School of Public Health noticed that in The Ozempic group had a higher incidence of non-arteritic ischemic optic neuropathies..
Ischemic optic neuropathies occur when arteries fail to supply blood to the optic nerve and are the second most common cause of vision loss after glaucoma. In non-arteritic inflammations, there are no arteries.
This condition affects about 10 out of every 100,000 people and is more common in men aged 50 years and older. It is usually associated with systemic hypertension, hyperlipidemia, sleep apnea or diabetes.
Among 194 people with diabetes taking semaglutide, 20 neuropathies occurred, compared with six in the group taking other drugs.
Thus, the researchers calculated that the risk of developing neuropathy after three years was 8.9% in the Ozempic group, compared with 1.8% in those taking the other drugs.
That means those who took the popular drug had a five-fold higher risk of vision loss.
The authors also assessed the effect of semaglutide in patients taking it as a weight-loss drug. In this case, of the more than 16,000 patients in the study (with no history of ischemic optic neuropathy), 361 were prescribed the drug, compared with 618 obese people who were given other treatments.
In the first of these groups, 20 events occurred, compared to three in the second. That is, People taking semaglutide were seven times more likely to suffer from this phenomenon..
In statements to The keeperJosep F. Rizzo, one of the study’s authors, noted that the results of this work were “significant but preliminary” and that the issue needs to be assessed in a wider population before conclusions can be drawn.
However, he cautioned that doctors needed to discuss any eye conditions, such as glaucoma, with their patients before prescribing these drugs.
Correlation does not imply causation.
It is important to keep in mind that this is an observational study, in which the researchers analyze patient data post-hoc and cannot intervene to exclude variables that may bias the results.
The authors of the study themselves acknowledge this, but note that “however, our analysis shows that potential confounding factors did not contribute significantly to the risk“.
However, there is no mechanism linking semaglutide use to ischemic optic neuropathy, they note.
“It was a surprise,” says the endocrinologist. Christopher Moralesmember of the Spanish Society for the Study of Obesity (SEEDO), “since one of the main modes of action of GLP-1 (the family of drugs to which semaglutide belongs) is neuroprotection: by reducing inflammation and improving glycemic control, neurological and ophthalmological phenomena will improve.
Morales emphasizes the fact that because this is an observational study, the association found “does not imply causation” and could be due to other factors that could not be identified.
“We are calm because during clinical trials and In real life, we have not yet found such an effect.and these are clinical trials that involved a lot of people.
The endocrinologist notes that there is a known connection between osempic and diabetic retinopathy, a complication of diabetes caused by damage to the blood vessels of the light-sensitive tissue of the retina.
“That is why the company itself organized a new clinical study called Focus, which will allow us to be confident in its safety at the ophthalmological level.”
A doctor who has been working with these types of drugs for nearly two decades wants to reassure patients who take them and think their health may be at risk.
However, when conducting such studies, it is useful to remember that “despite the high safety profile, they should always be performed as prescribed and under the supervision of a physician.”