Personalized management of acenocoumarol dosage using eGFR: Analysis of INR data in a cohort of 204 patients

Acenocoumarol is a widely used vitamin K antagonist, particularly in European countries. While age and body metrics are known to influence dose requirements, the role of renal function in guiding acenocoumarol dosage remains underexplored.

The primary aim of this study was to investigate the relationship between renal function and the weekly dose of acenocoumarol required to maintain therapeutic international normalized ratio (INR) levels.

We analyzed 425 INR measurements from 204 adult patients receiving acenocoumarol, stratified by target INR ranges of 2.00 - 3.00 and 2.50 - 3.50. Renal function was assessed using the body surface area (BSA)-adjusted chronic kidney disease-epidemiology (CKD-EPI) 2021 formula. Weekly acenocoumarol doses were evaluated in relation to age, sex, estimated glomerular filtration rate (eGFR), and body size.

Patients with lower eGFR and older age required significantly lower weekly doses of acenocoumarol. In the INR 2.00 - 3.00 group, males required higher doses than females, correlating with both greater body size and higher eGFR. However, in the INR 2.50 - 3.50 group, males and females received the same median dose despite differing body metrics, mirroring their similar renal function. A positive correlation was found between BSA-adjusted eGFR and weekly dose, particularly when eGFR exceeded 90 mL/min (Spearman r = 0.48, p = 0.0001).

Renal function, as measured by BSA-adjusted eGFR, is a critical determinant of acenocoumarol dose requirements. These findings support the inclusion of renal function in future acenocoumarol dose calculators and emphasize the importance of individualized dosing strategies.