Trough Concentration Deficiency of Rivaroxaban in Patients With Nonvalvular Atrial Fibrillation Leading to Thromboembolism Events

Abstract: This retrospective study investigated factors influencing the steady-state trough concentrations (Ctrough) of rivaroxaban in patients with nonvalvular atrial fibrillation (NVAF). We retrieved data from patients with NAVF who first started rivaroxaban anticoagulation at the Fujian Provincial Hospital from October 2017 to October 2020 through the electronic medical record system. Patients were followed for 1 year after the first dose of rivaroxaban, and the primary efficacy and safety end points were recorded. All follow-up visits were completed by October 2021. A Ctrough of <12 ng/mL was defined as Ctrough deficiency. Factors that influenced rivaroxaban Ctrough deficiency were investigated using multivariate binary logistic regression analysis. Kaplan–Meier survival curve analysis was used to determine differences between Ctrough deficiency and event-free survival. A total of 167 patients with NVAF were enrolled in the study, including 113 men and 54 women, with an average (± SD) age of 70.40 ± 12.46 years. High albumin levels were an independent protective factor against Ctrough deficiency (odds ratio, 0.932; P = 0.031). Ctrough deficiency was associated with the probability of freedom from thrombotic events (P = 0.004); however, there were no significant differences in the probability of freedom from bleeding events (P > 0.05). In conclusion, among the variables studied, a low albumin level was the main contributor to Ctrough deficiency. Rivaroxaban Ctrough deficiency also increased thrombotic events, but this was not associated with hemorrhagic events in Chinese patients with NVAF.