Weight-Based Dosing Versus a Fixed-Dose Regimen of 4-Factor Prothrombin Complex Concentrate in Obese Patients Requiring Vitamin K Antagonist Reversal.

INTRODUCTION Despite an increase in the use of fixed-dose protocols of 4-factor prothrombin complex concentrate (4F-PCC) for the reversal of vitamin K antagonists (VKAs), there remains a paucity of data in obese patients. In this study, we aimed to compare the proportion of patients attaining international normalized ratio (INR) goals using a weight-based dosing strategy versus a fixed-dose regimen of 4F-PCC. METHODS This was a retrospective study conducted in patients 18 years of age or older, weighing ≥ 100 kg, who received either a weight-based dose or fixed dose of 4F-PCC (2000 units) for the reversal of VKA, and had a documented baseline and post-treatment INR. The primary outcome was the proportion of patients achieving an INR of < 2 for all indications of warfarin reversal, except in patients with intracranial hemorrhage, where the goal was an INR of < 1.5. RESULTS A total of 44 patients met the inclusion criteria; 25 patients in the weight-based dosing group and 19 patients in the fixed-dose group. The median baseline INR was similar in both groups (weight-based dosing group 3.2 [interquartile range {IQR} 2.8-3.7] vs fixed-dose group 3.0 [IQR 2.7-4.9], p = 1). The median post-treatment INR was significantly lower in the weight-based dosing group compared to the fixed-dose group (1.3 [IQR 1.2-1.5] vs 1.6 [IQR 1.5-1.9], p < 0.01). However, there was no significant difference in the primary outcome between both groups (weight-based dosing strategy 84% vs fixed dose strategy 90%, p = 0.68). CONCLUSION Our findings suggest that a fixed-dose regimen of 2000 units in obese patients weighing ≥ 100 kg is adequate to achieve these INR goals.