A new observational study has identified a potential link between Novo Nordisk A/S’s GLP-1 drugs, Ozempic and Wegovy (semaglutide), and a serious eye condition known as nonarteritic anterior ischemic optic neuropathy (NAION), which can lead to vision loss.

NAION refers to a loss of blood flow to the optic nerve (the cable that connects the eye to the brain). This condition typically causes sudden vision loss in one eye without any pain.

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The study revealed that individuals with diabetes who received and filled a semaglutide prescription were over four times more likely to be diagnosed with NAION.

Additionally, those who were prescribed semaglutide and were overweight or obese had more than seven times the risk of receiving this diagnosis.

The study reviewed 710 patients with type 2 diabetes, finding that 17 cases of NAION occurred in those prescribed semaglutide, equivalent to a cumulative rate of 8.9% over three years.

Comparatively, six cases were found among patients using non-GLP-1 diabetes drugs, yielding a cumulative rate of 1.8%. Statistical analysis estimated that semaglutide users had a 4.28 times greater risk of developing NAION.

In a separate cohort of 979 overweight or obese patients, 20 cases of NAION were identified in those prescribed semaglutide, resulting in a cumulative rate of 6.7%. Only three cases were found in patients using non-GLP-1 obesity drugs, with a cumulative rate of 0.8%.

This indicated a 7.64 times greater risk for semaglutide users.

Several study limitations were noted. Mass Eye and Ear treats a disproportionately high number of individuals with rare eye diseases, the study population is predominantly white, and there were relatively few NAION cases over the six years, making the statistics volatile.

Additionally, the researchers couldn’t confirm whether patients consistently took their medication or if they started and then stopped semaglutide, which could have affected their risk.

The study does not establish causality, and the researchers are uncertain about the reasons behind the observed association or the differences between diabetic and overweight groups.

Price Action: NVO shares are down 3.85% at $137.48 at last check Wednesday.

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