Retinal vein occlusion and the risk of stroke development: a 9-year nationwide population-based study

Purpose: To evaluate the risk of stroke development after retinal vein occlusion (RVO).

Design: Nationwide, population-based 9-year longitudinal study.

Participants: National registry data were collected from the Korean National Health Insurance Research Database, comprising 1 025 340 (∼2.2%) random subjects who were selected from 46 605 433 Korean residents in 2002.

Methods: Patients diagnosed with RVO or stroke in 2002 were excluded. The RVO group was composed of patients with an initial diagnosis of central or branch RVO between January 2003 and December 2005 (n = 344 in 2003, 375 in 2004, and 312 in 2005). The comparison group was composed of randomly selected patients (5 per patient with RVO; n = 1696 in 2003, 1854 in 2004, and 1524 in 2005) who were matched to the RVO group according to age, sex, residential area, household income, and year of RVO diagnosis. Each sampled patient was tracked until 2010. Cox proportional hazard regressions were used to calculate the overall survival rate for stroke development after adjusting for potential confounders, including hypertension, diabetes mellitus, and chronic kidney disease.

Main outcome measures: Retinal vein occlusion and ischemic or hemorrhagic stroke based on the International Classification of Disease codes.

Results: Stroke developed in 16.8% of the RVO group and in 10.7% of the comparison group. Retinal vein occlusion was associated with an increased risk of stroke development (hazard ratio [HR], 1.48; 95% confidence interval [CI], 1.24-1.76). Hypertension, diabetes mellitus, and chronic kidney disease also increased the risk of stroke development. In addition, RVO increased the risk of both ischemic stroke (HR, 1.51; 95% CI, 1.24-1.84) and hemorrhagic stroke (HR, 1.30; 95% CI, 0.83-2.05), although this result was not significant for hemorrhagic stroke. In terms of age, the effect size of the HR was largest among younger adults, aged <50 years (HR, 2.69), compared with middle-aged adults, aged 50 to 69 years (HR, 1.33), and older adults, aged ≥70 years (HR, 1.46).

Conclusions: Retinal vein occlusion was significantly associated with stroke development after adjusting for potential confounders. These findings are limited by uncontrolled confounding and need to be replicated by other observational studies.