Study links semaglutide and tirzepatide to higher rate of rare optic nerve diagnoses
A large records study found a small but higher rate of optic nerve diagnoses in type 2 diabetes patients prescribed semaglutide or tirzepatide, with both drugs analyzed as one group.
A study of US electronic health records found that adults with type 2 diabetes who were prescribed semaglutide (Ozempic, Wegovy, Rybelsus) or tirzepatide (Mounjaro, Zepbound) were diagnosed with a rare optic nerve condition more often than matched patients taking other diabetes medicines, though the overall risk in both groups was low [1].
The research, published in JAMA Network Open, emulated target trials using a nationwide, population-based database of US patient records from December 2017 to January 2023 [1]. From 1,511,637 eligible patients, the researchers matched 159,398 people with type 2 diabetes who had no prior diagnosis of eye disorders: 79,699 prescribed semaglutide or tirzepatide and 79,699 prescribed another antidiabetic medication. The average age was 56.5 years (SD, 13.3), and 83,123 participants (52.15%) were women [1].
Over two years of follow-up, nonarteritic anterior ischemic optic neuropathy (NAION) was diagnosed in 35 patients (0.04%) in the semaglutide-or-tirzepatide group and 19 patients (0.02%) in the comparison group, a hazard ratio of 1.76 (95% CI, 1.01-3.07) [1]. Other optic nerve disorders were diagnosed in 93 patients (0.12%) in the drug group and 54 patients (0.07%) in the comparison group, a hazard ratio of 1.65 (95% CI, 1.18-2.31) [1]. The study found no association with other disorders of the optic nerve or visual pathways [1].
The comparison group took insulins, metformin, dipeptidyl-peptidase-4 inhibitors, sodium-glucose cotransporter-2 inhibitors, sulfonylureas, thiazolidinediones or other glucagon-like peptide-1 receptor agonists [1].
Two limits shape how the results should be read. The study analyzed semaglutide and tirzepatide as a single exposure, so it cannot show whether the risk differs between the two drugs or whether one of them accounts for the finding [1]. And every participant had type 2 diabetes; whether a similar pattern appears in people who take these drugs for obesity without diabetes has not been reported [1]. The abstract also notes that earlier reports of an NAION link with these drugs were inconsistent [1].
Why it matters for patients
The absolute numbers were small. The NAION rate of 0.04% in the drug group works out to about 4 diagnoses per 10,000 people over two years, compared with about 2 per 10,000 in the comparison group [1]. The confidence interval for NAION, 1.01 to 3.07, sits close to 1.0 at its lower end, meaning the size of the effect is not precisely pinned down [1].
The study's authors concluded that patients prescribed these drugs had an increased risk of NAION and other optic nerve disorders "although the overall risk was low," and wrote that the findings "highlight the need for close monitoring of these conditions" [1]. The study does not report what happened to the patients after diagnosis, such as whether their vision was affected over time, and it offers no comparison of one drug against the other [1].
What happens next
Whether regulators or the manufacturers will change prescribing information in response has not been reported [1]. Whether the two drugs carry different levels of risk also has not been reported; separating them would require a study built for that comparison [1]. A separate comment article accompanied the study [1].
Sources
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