Increased Risk of Stroke in Patients With Nonarteritic Anterior Ischemic Optic Neuropathy: A Nationwide Retrospective Cohort Study

PurposeTo investigate the incidence and prevalence of nonarteritic anterior ischemic optic neuropathy (NAION), and to extrapolate the risk of cerebrovascular events following NAION.DesignRetrospective cohort study.MethodsWe identified NAION patients first, and then looked for the diagnosis of stroke after the diagnosis of NAION. Setting: The study group was composed of patients diagnosed with NAION seeking ambulatory care from 2000 to 2011. The control group was extracted from a database by randomly selecting 2 patients for every NAION patient, matched by age and sex. Main Outcome Measures: Cox proportional hazards regression analysis was performed to calculate adjusted hazard ratio (aHR) of stroke for the 2 groups. Subgroup analysis of subjects with or without comorbidities was also investigated.ResultsFour hundred and fourteen patients were included in the study group and 789 in the control group. The mean follow-up period was 5.9 years. The incidence of NAION was 3.72/100 000 person-years in Taiwan, and the prevalence of NAION was 48.18/100 000 persons. The study group was more likely to have ischemic stroke (aHR = 2.03, P = .003), but not hemorrhagic stroke (aHR = 1.24, P = .696), than the control group. Among the subgroup with comorbidities, the risk of ischemic stroke among the subjects with NAION was 3.35 times higher than those without NAION (95% confidence interval: 1.67, 6.70).ConclusionsPatients with NAION have an increased risk of ischemic stroke. Physicians should refer all patients with NAION for systemic survey of vasculopathy and control of modifiable risk factors to prevent irreversible neurological sequelae.