Elevated Stroke Risk Following NAION

Nonarteritic anterior ischemic optic neuropathy (NAION) is significantly associated with persistently elevated risk for stroke, independent of typical cardiovascular risk factors, a large multinational cohort study showed. 

Stroke risk was three to five times higher in the first 3 months following NAION diagnosis, and the risk remained high over 10 years of follow-up, which supports NAION as an independent risk factor for stroke, investigators concluded.

“These findings underscore the importance of regular stroke workups following the onset of NAION,” researchers wrote.

The study was published online on November 12 in JAMA Network Open. 

Long-Term Stroke Risk 

NAION is characterized by acute vision loss primarily affecting adults aged > 50 years and is one of the chief causes of blindness. NAION shares risk factors with stroke, such as hypertension and diabetes, but whether it directly increases stroke risk remains unclear. 

Shu-Chun Kuo, MD, with Chi-Mei Medical Center, Tainan City, Taiwan, and colleagues, investigated stroke risk following NAION in a large, diverse, multinational cohort.

Leveraging electronic health record data from the Global Collaborative Network of TriNetX, they created a propensity score-matched cohort of nearly 90,000 patients with NAION and a like number without the condition.

Patients with NAION had a significantly higher risk for all strokes at 1 and 3 months (relative risk [RR], 5.04 and 3.79, respectively) and at 1, 5, and 10 years (RR, 2.50, 1.54, and 1.33, respectively), irrespective of comorbid conditions.

Patients with NAION had an elevated risk for both ischemic and hemorrhagic strokes, but ischemic stroke was more common.

Among all clinical factors of interest, only hypertension was consistently associated with all subtypes of stroke following NAION, researchers wrote. 

More Research Needed

They acknowledged the potential for misclassification bias, due to reliance on the International Classification of Diseases–10th edition diagnosis codes for identifying outcomes and conditions, including NAION. Additionally, the TriNetX database lacks precise information on lifestyle factors and blood pressure.

The findings point to the need for regular stroke workups following the onset of NAION, the study team concluded.

Reached for comment, Larry Goldstein, MD, chair, Department of Neurology, University of Kentucky, Lexington, told Medscape Medical News that while the occurrence of NAION should alert patients and clinicians to increased stroke risk, it’s unclear “whether there is anything actionable, aside from attention to and management of both lifestyle (diet, exercise, tobacco use, alcohol consumption, etc.) and medical stroke risk factors (hypertension, lipid disorders, etc.), which should be done in everyone.”

“There are no data presented regarding an association with specific stroke subtypes (eg, cariogenic embolism, large vessel extracranial atherosclerosis, intracranial large vessel disease, small vessel disease, etc.) to otherwise guide ‘stroke workups,’” said Goldstein, who was not involved in the study.

The study had no specific funding. Kuo and Goldstein had no relevant disclosures.