Organizations speak out about weight loss drug linked to rare blindness

Medical societies have joined forces to release a statement clarifying a recent study that linked semaglutide-based weight-loss drugs — such as Ozempic, Rybelsus and Wegovy — to an increased risk of a rare type of blindness called Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION).

O statementsigned by the Brazilian Diabetes Society (SBD), Brazilian Association for the Study of Obesity and Metabolic Syndrome (Abeso), Brazilian Society of Endocrinology and Metabolism (SBEM) and Brazilian Society of Ophthalmology (SBO), was published on the 12th.

In the note, the entities state that they analyzed the study in detail through their scientific committees, and that they have come out publicly to provide an opinion aimed at people with diabetes and obesity who are using, or intend to start, treatment with semaglutide.

“The SBD, ABESO, SBEM and SBO recognize that, although there may have been an increase in the relative risk of NAION in people using semaglutide, the increase in absolute risk was very low, and should not be a reason to suspend the medication,” the document states.

The study, published in JAMA Ophthalmology in early July, showed a link between the use of semaglutide medications and NAION, a type of ocular stroke that causes sudden, painless loss of vision in one eye.

According to the workof the total number of patients with neuro-ophthalmological diseases who underwent consultation between 2017 and 2023 (710 people with diabetes and 979 with obesity), 555 were using semaglutide. Among these, there were 37 cases of NAION (6.6%). In 1,134 people with diabetes or obesity, not using semaglutide, there were 9 cases of NAION (0.79%).

Entities’ recommendations

Societies recommend that the retinal examination is performed routinely and periodically as part of the medical monitoring of people with diabetes. In addition, they state that, in the case of patients who have already had NAION or who have sudden or recent loss of vision, semaglutide should be immediately withdrawn from treatment and the patient undergoes an ophthalmological examination as soon as possible.

“The use of semaglutide should continue to be normally indicated in asymptomatic people, but only by doctors, and its use without a prescription and for weight loss in people who are not obese or overweight with comorbidities is strongly condemned,” the note highlights.

“To date, there is no evidence of causality between the use of semaglutide and the emergence of NAION. However, new studies, especially large real-life studies dedicated to evaluating ocular health in patients using semaglutide, are expected to clarify this issue,” he adds.

Entities point out limitations of the study

In the document, the entities emphasize that the study’s findings “were obtained in a population at much higher risk, which limits the validity of extrapolating these results to people in the general population.” They refer to the fact that the study was conducted on patients who received medical care at a clinic specializing in neuro-ophthalmology, and not on the general population.

Another point considered by the entities is that the study was observational and not randomized, “that is, the people who used semaglutide were not randomly selected to receive the medication, but rather chosen from medical records to be included in the study according to their previous use. Therefore, there is no way to affirm that the people in the study who used semaglutide had, in fact, a risk of NAION similar to that of people who did not receive semaglutide”, they say.

The document also highlights that risk factors such as smoking, duration of diabetes and optic disc morphology were not taken into account by the study.

“If the group that received semaglutide had a greater number of risk factors at the beginning of the study, this would obviously explain the greater number of cases of NAION in this group. Therefore, it is not possible to conclude that there is a cause and effect relationship between the use of semaglutide and the emergence of NAION in this study. There is no way to affirm, with these data, that semaglutide caused an increase in cases of NAION,” the entities state.

Diabetes and obesity drug may increase risk of rare blindness