PGY2 Internal Medicine Pharmacy Residency

Apixaban and rivaroxaban anti-Xa level monitoring versus standard monitoring in hospitalized patients with acute kidney injury

William Towers, PharmD; Steffany N. Nguyen, PharmD; Melanie C. Ruegger, PharmD; Eric Salazar, MD, MPH; Kevin R. Donahue, PharmD

PURPOSE Oral direct factor Xa inhibitors (FxaI) are commonly used anticoagulants for stroke prevention in atrial fibrillation and the treatment of venous thromboembolism. As FxaIs are renally eliminated, acute kidney injury (AKI) may increase risk for drug accumulation and bleeding. There is minimal data describing the effects of AKI on anti-Xa levels or clinical outcomes in patients receiving a FxaI. The purpose of this study was to compare anti-Xa level monitoring to standard monitoring in patients who experience AKI on apixaban or rivaroxaban.

METHODS

This retrospective cohort study included adult patients admitted within the Houston Methodist (HM) System from May 2016 to October 2020 and was approved by the HM Research Institute Institutional Review Board. Patients were included if they received apixaban or rivaroxaban within 72 hours prior to AKI. Patients with a history of end-stage kidney disease requiring kidney replacement therapy prior to admission were excluded. Patients were stratified into one of two groups, those with anti-Xa level monitoring or those who received standard monitoring. The primary outcome was major bleeding as defined by the International Society of Thrombosis and Haemostasis.

RESULTS

A total of 196 patients were included in the final analysis. Major bleeding occurred in two patients who received anti-Xa level monitoring compared to 14 patients who received standard monitoring (2.1% versus 14%; p<0.01). Variables identified as predictors of major bleeding included a documented history of liver (odds ratio 3.17; 95% confidence interval, 1.04-9.67; p=0.04) and antiplatelet use (odds ratio 4.18; 95% confidence interval, 1.28-13.7; p=0.02).

CONCLUSION

Anti-Xa level monitoring was associated with a significant reduction in major bleeding compared to standard monitoring. A history of liver disease and antiplatelet use may increase the risk of bleeding in patients who develop AKI while receiving apixaban or rivaroxaban. The optimal management of antithrombotic medications in patients with AKI and recent exposure to a FxaI requires further investigation.

PGY2 INTERNAL MEDICINE PHARMACY RESIDENCY

William Towers, PharmD, BCPS

Will earned his BS in Biomedical Sciences from Auburn University in 2015 and PharmD from the Auburn University Harrison School of Pharmacy in 2019. He completed his PGY1 residency at Methodist University Hospital in Memphis, TN. Following completion of his PGY2, he will assume the role of internal medicine pharmacy specialist at MD Anderson Cancer Center in Houston, Texas. Primary project preceptor: Kevin Donahue, PharmD, BCPS

Presented at 2020 Virtual Vizient Pharmacy Network; 2021 Virtual Midwest Pharmacy Residents Conference.