Factors Associated with Bleeding Events in Patients Receiving Rivaroxaban for Venous Thromboembolism: A Real World Experience
Authors: Mangla Ankit , Mushtaq Muhammad Umair , Paydary Koosha , Mann Hashim , Liu Jiaxiang , Krishnan Jayasree , Akhtar Tauseef , Mattumpuram Jishanth , Putta Aakash , Uprety Alok , Wang Yanting , Yim Barbra , Lad Thomas 
Published: October 2019

Abstract
Introduction:
Rivaroxaban is a target specific oral anticoagulant approved for treatment of deep venous thromboembolism (DVT), pulmonary embolism (PE) and risk reduction in patients with DVT/PE requiring continued anticoagulation. The XALIA study showed a reduced bleeding risk compared to standard anticoagulation therapy; however, there is paucity of data regarding correlates of bleeding risk amongst patients receiving rivaroxaban in the community setting. We aimed to investigate the clinical factors associated with bleeding events (BE) in patients receiving rivaroxaban for treatment of DVT/PE.
Methods:
A retrospective study was conducted at John H. Stroger, Jr. Hospital of Cook County. We screened the charts of 837 patients who received rivaroxaban from January 1, 2015 to April 01, 2018. Patients with DVT/PE were included in the study (n=271). Patients with atrial fibrillation and those receiving rivaroxaban for prophylaxis were excluded. Any reported BE was recorded as either major or minor bleeding event. Major BE was defined as events requiring hospitalization, blood transfusions or significant drop in hemoglobin (>2gm/dL). Rest of the BE were classified as minor BE. Socio-demographic and clinical factors were collected. Chi-square test and fisher exact test were used as the tests of trend. Multivariate logistic regression models were used to quantify the independent predictors. Odds ratios (OR) and adjusted odds ratios (aOR) with 95% confidence intervals (CI) were obtained.
Results:
The study included 271 patients, of which 68.3% were African-American, 14.4% were Caucasian, and 12.9% were Hispanic. Median age was 53 years and 60.9% patients were men. Bleeding events were reported in 11.4% (n=31) patients with 6.3% major bleeding events and 5.2% minor bleeding events. Only concurrent use of aspirin (23.8% vs. 9.2%; OR 3.10, 95% CI 1.34-7.17, P = 0.008) was significantly associated with bleeding events. None of the clinical parameters, like abnormal liver function tests (11.4%), cirrhosis (3.3%), chronic kidney disease stage 3 or worse (7.6%), prior use of warfarin (29.9%) or low molecular weight heparin (18.1%) were associated with bleeding events. In multivariate model adjusted for age, gender and race, concurrent use of aspirin (aOR 3.06, 95% CI 1.23-7.62, P = 0.017) remained independent predictor of bleeding events.
Conclusion:
In the community practice, aspirin (81mg or 325mg) is prescribed for cardio-protection. A recently concluded trial showed a better cardioprotective effect of combining rivaroxaban and aspirin, without increase in BE in patients with stable cardiovascular disease. However, such data is not evident in patients receiving rivaroxaban for DVT/PE. Our study shows an increased rate of bleeding events in such patients with concurrent use of aspirin. Our study population comprises of two-third African-American patients who are under-represented in the clinical trials. Based on our results we would suggest further investigation in safety of prescribing aspirin with rivaroxaban in patients with DVT/PE in prospective trials.

Disclosures
No relevant conflicts of interest to declare.