Albumin and Bleeding Risk in Hospitalized Patients Receiving Apixaban

Highly protein bound anticoagulants such as warfarin and rivaroxaban have increased therapeutic effects in the setting of hypoalbuminemia due to increased free concentrations in the drug which result in increased bleed risk. Apixaban is also heavily protein bound at 87% but bleeding in hypoalbuminemic patients receiving apixaban has largely been unevaluated. Therefore, this retrospective, cohort study of hospitalized adults who received apixaban and had a serum albumin level measured was conducted. Included patients were evaluated for bleeding events in accordance with International Society on Thrombosis and Hemostasis (ISTH) criteria. Patients were grouped by bleeding status (bleed vs non bleed) and multivariable logistic regression modeling was used to evaluate the relationship between albumin, co-variables, and bleeding events. A total of 391 patients were included, 49 that bled and 342 that did not. Multivariable modeling determined a significant association between bleeding events and serum albumin level (adjusted odds ratio 2.10 for every 1 g/dL reduction in serum albumin, 95% confidence interval: 1.26 – 3.60), high risk IMPROVE Bleeding scores (adjusted odds ratio 2.17, confidence interval: 1.127 – 4.181) and active gastroduodenal ulcer (adjusted odds ratio 5.20, confidence interval: 1.11 – 24.39). Consideration of serum albumin levels may be relevant when treating patients with highly protein bound anticoagulants such as apixaban.