A global retrospective cohort study has revealed a significantly increased risk of stroke in patients with nonarteritic anterior ischemic optic neuropathy compared to matched controls, independent of comorbidities. Conducted across 17 countries using data from more than 152 million patients in the TriNetX Global Collaborative Network, the research assessed stroke risk over short- and long-term intervals.
Nonarteritic anterior ischemic optic neuropathy (NAION), a sudden but painless loss of vision, is among the most common optic neuritis in people 50 or older, the researchers noted in their recent JAMA article. NAION shares several risk factors with stroke including diabetes, obstructive sleep apnea, smoking, dyslipidemia, hypertension, and cardiovascular disease. Investigations into the potential increased risk of stroke in NAION patients are still being explored and associations between the conditions remain under debate.
This study applied rigorous propensity score matching for confounders such as age, sex, comorbidities, and medication use to electronic health records from January 2004 to March 2024. The matched cohorts comprised 89,811 patients each with NAION and cataracts (control group). Rate of stroke was assessed at time intervals of 1 month, 3 months, 1 year, 5 years, and 10 years after NAION onset.
Investigators found that patients with NAION had an elevated relative risk (RR) of stroke:
- 1 month: RR 5.04
- 1 year: RR 2.50
- 10 years: RR 1.33
Sensitivity analysis excluding patients with comorbidities also confirmed NAION as an independent risk factor for stroke:
- 1 month: RR 7.55
- 10 years: RR 1.68
Both ischemic and hemorrhagic strokes showed increased incidence. Notably, hemorrhagic stroke risk was elevated in the NAION group compared to controls.
The study acknowledged potential misclassification bias due to reliance on diagnostic codes and limitations in capturing detailed lifestyle and metabolic data. Despite its limitations, the study’s international scope and sample size support the conclusion that “NAION is independently associated with increased stroke risk, regardless of the presence of comorbidities,” the researchers concluded.
They noted that associations between small vessel disease (SVD) and NAION should also be explored, given the incidence of SVD with ischemic stroke. They recommended regular stroke work-ups after the onset of NAION.
A full list of author disclosures can be found in the published research.
