Risk of intraocular bleeding with novel oral anticoagulants compared with warfarin: a systematic review and meta-analysis

Abstract

Importance: It is unclear if the risk of intraocular bleeding with novel oral anticoagulants differs compared with warfarin. Objective: To characterize the risk of intraocular bleeding with novel oral anticoagulants compared with warfarin. Data Sources: A systematic review and meta-analysis was undertaken in an academic medical setting. MEDLINE and ClinicalTrials.gov were searched for randomized clinical trials published up until August 2016. This search was supplemented by manual bibliography searches of identified trials and other review articles. Study Selection: Studies were eligible for inclusion if they were phase 3 randomized clinical trials, enrolled patients with atrial fibrillation or venous thromboembolism, compared a novel oral anticoagulant (dabigatran, rivaroxaban, apixaban, or edoxaban) with warfarin, and recorded event data on intraocular bleeding. Data on intraocular bleeding were pooled using inverse-variance, weighted, fixed-effects meta-analysis. Data Extraction and Synthesis: The PRISMA guidelines were used for abstracting data and assessing quality. Independent extraction was performed by 2 investigators. Main Outcomes and Measures: Intraocular bleeding events and associated risk ratio for novel oral anticoagulants compared with warfarin. Results: Twelve trials investigating 102 627 patients were included. Randomization to novel oral anticoagulants was associated with a 22% relative reduction in intraocular bleeding compared with warfarin (risk ratio, 0.78; 95% CI, 0.61-0.99). There was no significant heterogeneity observed (I2 = 4.8%, P = .40). Comparably lower risks of intraocular bleeding with novel oral anticoagulants were seen in subgroup analyses, with no significant difference according to the indication for anticoagulation (P for heterogeneity = .49) or the novel oral anticoagulant type (P for heterogeneity = .15). Summary estimates did not differ materially when random-effects meta-analytic techniques were used. Conclusions and Relevance: These results suggest that novel oral anticoagulants reduce the risk of intraocular bleeding by approximately one-fifth compared with warfarin. Similar benefits were seen in both patients with atrial fibrillation and venous thromboembolism. Our data have particular relevance for patients at higher risk of spontaneous retinal and subretinal bleeding. These findings may also have important implications in the perioperative period, in which the use of novel oral anticoagulants may be superior. Future studies are required to better characterize the optimal management of patients with both ophthalmic disease and cardiovascular comorbidities requiring anticoagulation.