Similarities and differences in systemic risk factors for retinal artery occlusion and retinal vein occlusion: A nationwide case-control study

Abstract Background: To investigate the relationship between risk factors of retinal artery occlusion (RAO) and retinal vein occlusion (RVO) and thereby identify similarities and differences between the two types of retinal vascular occlusions. Methods: In this case-control study, 5997 RAO patients were included and matched with three RVO patients each. The RVO patients were matched on sex and age at index date. All patients, personal information, diagnoses, and prescriptions were obtained from the Danish nationwide registries. Adjusted conditional logistic regression was used to investigate the association of RAO and RVO with the included risk factors. Results: RAO was stronger associated with arterial hypertension, heart failure, ischemic heart disease, peripheral artery disease, renal disease, and stroke than RVO, with effect measures ranging from 1.13-2.08. RVO was inversely associated with atrial fibrillation, cataract, and glaucoma with effect measures of 0.84 (95% CI: 0.75-0.95), 0.83 (95% CI: 0.76-0.90) and 0.45 (95% CI: 0.40-0.52), respectively. Conclusion: Differences in the level of associations with the included risk factors suggests differences in the pathophysiologies of the two diseases. The main pathophysiology associated with RAO was atherosclerosis, whereas the main pathophysiology associated with RVO were changes in the pressure gradients of the eyes.