Abstract 13532: A Case Series Assessing the Suitability of Treatment with Apixaban Based on Renal Function
Introduction: Clearance of the new oral anticoagulants (NOACs) relies in part on renal function. Before prescribing a NOAC, renal function should be estimated by calculating creatinine clearance (eCrCl). The European Society of Cardiology recommends calculating eCrCl using the Cockcroft Gault (CG) calculation.
Although estimated glomerular filtration rate using the Modification of Diet in Renal Disease method (eGFR MDRD) allows staging of renal function to facilitate monitoring and treatment of chronic kidney disease (CKD), it was not designed for drug dosing decisions, while the CG equation has been used for estimating renal function for drug use and dosing.
The CG equation is considered the gold standard for assessment of kidney function in the United States; however, most laboratories in Australia and Europe provide the eGFR-MDRD results only. If the decision to treat with NOACs is based on the eGFR-MDRD calculation, at-risk patients (e.g., extreme ends of weight and age) may seem eligible for treatment with a NOAC. In these borderline patients, clinicians should calculate eCrCl using the CG equation. Online calculators exist; this is not always a simple calculation.
Methods: In the table below we present a case series of 10 patients comparing their renal function using the eGFR-MDRD vs. the Cockcroft Gault calculation to determine suitability for treatment with apixaban. In Australia, treatment with apixaban based on the clinical trial protocol requires a CG ≤ 25 mL/min.
Summary: When assessing the suitability of NOACs in renally impaired patients, eGFR MDRD may overestimate the level of renal function. To better identify patients suitable for NOAC treatment, we recommend that Australian and European laboratories be required to report the CG calculation. This small change in laboratory results could improve patient outcomes. We also recommend the expansion of NOAC guidelines to provide clear guidance about the requirements for follow-up in borderline patients.
Author Disclosures: B. Norcock: None. J. Newman: Employment; Significant; Full Time Employee of Bristol-Myers Squibb. C. de Reuck: Employment; Significant; Full time employee of Bristol-Myers Squibb. F. Rhodes: None.
- © 2014 by American Heart Association, Inc.