A recent study has identified a potential association between the drug semaglutide and non-arteritic anterior ischemic optic neuropathy (NAION), a form of sudden vision loss. This study, which analyzed data from over 44,000 individuals in Denmark and nearly 17,000 in Norway, found that users of semaglutide may have an elevated risk of developing NAION. While the absolute risk remains low, the findings suggest that one additional person out of 10,000 semaglutide users could develop NAION annually.
The study, initiated following earlier research from the United States, focused on individuals eligible for semaglutide for type 2 diabetes management. In Denmark, 24 semaglutide users developed NAION, while in Norway there were eight cases. Researchers divided participants into two groups: those who received a semaglutide prescription and those who did not. The analysis revealed heightened rates of NAION in the semaglutide cohort.
Experts have been cautious about interpreting these findings. They emphasize that there is no definitive evidence to suggest semaglutide directly causes NAION, only that there may be an association. Investigators attempted to address potential confounders and selection bias, arriving at conclusions similar to previous studies.
"Although there are some interesting studies on the topic, it is premature to conclude that the association between semaglutide and NAION is a causal association," – Andrew Lee
"The investigators performed several analyses to address potential confounders and selection bias and came to a similar conclusion as [the previous study], that NAION may be linked to semaglutide or GLP-1s." – Beverly Tchang
The study's authors acknowledge the limitations of using a dataset confined to patients who had contact with specialist ophthalmologists or neuro-ophthalmologists, which complicates drawing definitive conclusions.
"but it is using a dataset that is quite peculiar, in that they only have data from patients that at some point had a contact to a specialist ophthalmologist [or neuro-ophthalmologist], which renders it quite difficult to draw conclusions from." – Pottegård
Despite these limitations, there is a biologically plausible mechanism for GLP-1, the class of drugs to which semaglutide belongs, to exacerbate diabetic eye problems. This could occur due to tighter blood sugar control leading to conditions akin to worsening diabetic retinopathy.
"There is a biologically plausible mechanism for GLP-1 to cause worsening diabetic eye problems from tighter blood sugar control analogous to the worsening of diabetic retinopathy in similar patients," – Andrew Lee
However, experts stress the overall risk of NAION remains very low.
"A person would have a very, very low chance of being that one in 10,000 person," – Beverly Tchang
"the overall risk of NAION, regardless of GLP-1 use, seems to be very low." – Beverly Tchang
Patients with a history of NAION are advised to consult their healthcare providers about the possible risks associated with semaglutide use. While these studies represent some of the first investigations into this phenomenon, more research is needed to fully understand the relationship between semaglutide and NAION.
“These are among the first studies to investigate this phenomenon,” – Anton Pottegård
Regulatory bodies are currently evaluating these findings to determine whether NAION should be recognized as a side effect of semaglutide. Given the current literature and study results, some researchers anticipate that such a recognition is likely.
“Now, regulators will evaluate the findings to see whether it should be listed. From my reading of the literature, including both our studies and other studies on this, I find it highly likely that it will be recognized as a side effect.” – Anton Pottegård
Nonetheless, for most users of semaglutide, this rare potential side effect should not be a significant concern.
“For the vast majority of users, there is no reason to consider this rare side effect,” – Anton Pottegård
Leave a Reply