The association of stroke with central and branch retinal arterial occlusion

Objectives To determine the near-term risk of stroke following a retinal artery occlusion (RAO). Methods The risk of stroke was assessed in two manners; with a self-controlled case series (SCCS) and a propensity score (PS) matched cohort study using a US medical claims database. The date of RAO diagnosis was assigned as the index date. In the SCCS, incidence of stroke was compared in 30- and 7-day periods pre- and post-index date. In PS analysis, matched cohorts were created from patients with RAO or hip fracture. Cox proportional hazard regression assessed the hazard for stroke. Patients were censored at 1 year, upon leaving the insurance plan or if they had a qualifying event for the comparison group. Results The SCCS included 16,193 patients with RAO. The incidence rate ratio (IRR) of new stroke in the month after RAO was increased compared to all periods >2 months before and all months after the index date (IRRs: 1.68-6.40, p < 0.012). Risk was increased in the week immediately following the index date compared to most weeks starting 2 weeks prior to and all weeks immediately after the index date (IRRs: 1.93-29.00, p < 0.026). The PS study analysed 18,213 propensity-matched patients with RAO vs. hip fracture. The HR for having a stroke after RAO compared to a hip fracture was elevated in all analyses (All RAO HR: 2.97, 95% CI: 2.71-3.26, p < 0.001; CRAO HR: 3.24, 95% CI: 2.83-3.70, p < 0.001; BRAO HR: 2.76, 95% CI: 2.43-3.13, p < 0.001). Conclusions The highest risk for stroke occurs in the days following a CRAO or BRAO, supporting guidelines suggesting immediate referral to a stroke centre upon diagnosis.