DOAC Dosing Discordance Using Different Estimates of Kidney Function and Outcomes

Area of Science:

• Pharmacology
• Nephrology
• Cardiology

Background:

• Direct oral anticoagulants (DOACs) are vital for preventing stroke in nonvalvular atrial fibrillation (NVAF).
• Current DOAC dosing guidelines rely on creatinine clearance (C-G) estimates.
• Estimated glomerular filtration rate (eGFR) from CKD-EPI is frequently used in clinical practice, creating potential dosing discrepancies.

Purpose of the Study:

• To assess DOAC dosing discordance between C-G and CKD-EPI equations.
• To investigate if this discordance impacts bleeding or thromboembolic events in NVAF patients.
• To emphasize appropriate DOAC selection and dosing for optimal patient outcomes.

Main Methods:

• Retrospective analysis of NVAF patients receiving rivaroxaban or dabigatran at UPMC Presbyterian Hospital (2010-2016).
• Inclusion criteria: adult patients with NVAF, DOAC prescription, and recent serum creatinine.
• Dosing discordance defined as CKD-EPI calculated dose differing from C-G based dose.

Main Results:

• Rivaroxaban dosing discordance occurred in 8% (49/644) of patients correctly dosed by C-G.
• Dabigatran dosing discordance occurred in 3% (17/590) of patients correctly dosed by C-G.
• Rivaroxaban discordance was associated with a significant increase in thromboembolism risk (OR, 2.83; 95% CI, 1.02-7.79; P=.045) when using CKD-EPI versus C-G.

Conclusions:

• DOAC dosing discordance is prevalent, especially with rivaroxaban, when using CKD-EPI instead of C-G.
• This discordance, particularly for rivaroxaban, is linked to a higher risk of thromboembolic events.
• Accurate kidney function assessment and adherence to guideline-recommended dosing are essential for managing NVAF patients on DOACs.