Health care claims for primary open-angle glaucoma and retinal vein occlusion from an 11-year nationwide dataset

To evaluate the risk of retinal vein occlusion (RVO) development after primary open-angle glaucoma (POAG) and the risk of POAG development after RVO, we conducted a nationwide, population-based 11-year longitudinal study. National registry data were collected from the Korean National Health Insurance Research Database, comparing 1 025 340 (~2.2%) subjects who were selected from 46 605 433 Korean residents in 2002. Each sampled patients was tracked until 2013. POAG developed in 0.92% of the RVO group (n = 6 826) and in 0.22% of the comparison group. RVO developed in 0.99% of the POAG group (n = 4 138) and in 0.37% of the comparison group. RVO was associated with an increased risk of POAG development (hazard ratio [HR], 3.25; 95% confidence interval [CI], 2.39–4.42) and POAG was associated with an increased risk of RVO development (HR, 5.05; 95% CI, 3.94–6.47). Comorbidity of systemic hypertension and diabetes mellitus further increased the risk of POAG development in the RVO group (HR, 3.58 and HR, 5.98, respectively). Patients with RVO exhibit a significantly higher risk of POAG development and patients with POAG exhibit a significantly higher risk of RVO development, based on an 11-year follow-up period.