Ischemic Stroke Risk in Medicare Beneficiaries with Central Retinal Artery Occlusion: A Retrospective Cohort Study

Introduction: To determine the incidence of ischemic cerebral stroke in the 6-month periods preceding and following acute central retinal artery occlusion (CRAO) among Medicare beneficiaries. Methods: A retrospective cohort study with comparison group conducted for calendar year 2013. Patients with CRAO were identified through National Medicare limited inpatient and institutional outpatient datasets for emergency services using ICD-9-CM code for CRAO (362.31). Patients with hip fractures (ICD-9-CM 820-820.9) during the same time period served as controls. Interval incident rates of ischemic stroke were determined from time-coded diagnoses of CRAO and hip fracture (index date zero) to date of principal discharge diagnosis of ischemic stroke (ICD-9-CM 434) recorded in the Medicare inpatient dataset. Risk of stroke was examined by comparing incidence among the two cohorts preceding and following the sentinel events. Results: There were 3338 patients with CRAOs during 2013. The incidence of ischemic stroke peaked the second week following CRAO relative to patients with hip fracture (relative incidence = 33.1 [95% confidence interval 9.8-84.6]). Conclusions: Medicare beneficiaries who present to emergency rooms with CRAO or are hospitalized directly for this condition were at highest risk of ischemic stroke in the first 2 weeks following the ocular diagnosis. Patients with acute CRAO should be promptly evaluated for stroke and stroke prevention.