Abstract 11599: Risk of Bleeding With Concomitant Use of Oral Anticoagulants and Aspirin: A Systematic Review and Meta-Analysis

Introduction: Oral anticoagulants (OAC) (e.g., warfarin, rivaroxaban, dabigatran) and salicylates (e.g., aspirin) can trigger the occurrence of bleeding events when used alone or in combination. Objective: The objective of this study was to conduct a systematic review and meta-analysis to examine the risk of bleeding in individuals exposed to a combination of OAC and aspirin, compared to those taking OAC monotherapy. Methods: PubMed, EMBASE, Scopus, and Web of Science were queried in January 2021. Studies that described combined exposure to OAC and salicylates, had a control arm of monotherapy of OAC and reported the number of bleeding events in each arm were included. After studies were identified for potential inclusion, first, the title and abstract were screened, followed by a review of the full text. The following information was extracted from the included studies: citation, drug and dose of medication, the average age of participants, number of patients and bleeding events in each group, and population of interest. Pooled odds ratios were calculated using a random-effects model. Heterogeneity was evaluated with Cochran’s Q and I2 statistics. Results: A total of 509 studies were identified, of which 35 met the inclusion criteria for the meta-analysis. Studies were further categorized into two groups based on the design of the study (randomized control trial or observational studies). Out of 35 studies, 16 randomized control trials compared combined OAC and salicylates vs warfarin monotherapy and combination therapy was associated with an increased odds [OR: 1.37, (95% CI 1.17 to 1.61)] of bleeding compared to warfarin monotherapy. The second group consisted of 19 observational studies comparing combined OAC and salicylates vs warfarin monotherapy. The results suggested that combination therapy was associated with an increased odds [OR: 1.42, (95% CI 1.09 to 1.87)] of bleeding compared to aspirin monotherapy. Conclusion: Risk of bleeding is significantly increased among patients taking salicylates and OAC together as compared with those taking warfarin alone.