Rivaroxaban for Thromboembolism Prophylaxis in Patients with Nephrotic Syndrome: A Single-Arm, Prospective Study.

INTRODUCTION

Thromboembolism is a recognized complication of nephrotic syndrome (NS). Evidence supporting the use of rivaroxaban to prevent NS-related thrombosis is limited and controversial. This study aimed to explore the impact of NS on rivaroxaban pharmacokinetics and to collect observational data on the efficacy and safety of rivaroxaban as primary thromboprophylaxis in patients with NS.

METHODS

This prospective study analyzed 141 patients with NS who received rivaroxaban (10 mg/day) for thromboprophylaxis. High-performance liquid chromatography-tandem mass spectrometry was used to measure the trough and peak plasma concentrations (C and C) of rivaroxaban. The influence of clinical and genetic factors on these concentrations was examined using multivariate logistic regression.

RESULTS

The median C and C were 68.5 ng/mL (interquartile range [IQR], 31.7-105.5 ng/mL) and 4.4 ng/mL (IQR, 1.2-11.9 ng/mL), respectively. The incidence of thromboembolic events (TEs) was 12.8%, while that of bleeding events was 14.2%, although all were classified as minor. Albumin level was the most significant factor affecting C (ρ = 0.55; < 0.001) and was also significantly associated with TEs (0.81; 0.71-0.91 per 1.0 g/dL increase; = 0.001) and bleeding risks (1.11; 1.03-1.19 per 1.0 g/dL increase; = 0.008). Single nucleotide polymorphisms in the gene significantly influenced C but were not associated with clinical outcomes.

CONCLUSION

Hypoalbuminemia significantly affects the pharmacokinetics of rivaroxaban in NS patients. A dose-adjustment strategy based on rivaroxaban concentrations, accounting for variable albumin levels, may improve the safety and efficacy of thromboprophylaxis in this population.