Monitoring Enoxaparin with Antifactor Xa Levels in Severe Renal Impairment

Abstract

Backgrounds: While several large clinical trials have proven the efficacy and safety of treatment with enoxaparin, most of these studies excluded patients with severe renal impairment and to date no large randomized studies have been conducted that assess the safety and efficacy of the drug in this subset of patients. Objectives: To characterize antifactor Xa peak levels as therapeutic, subtherapeutic, or supratherapeutic, in nondialysis patients with severe renal impairment who are receiving renally adjusted therapeutic doses of enoxaparin and to assess the incidence of bleeding complications in these patients. Methods: Retrospective cohort study in a community hospital evaluating seventy-five severe renal impairment patients (creatinine clearance [CrCl] < 30 mL/min) who received at least three renally adjusted therapeutic doses of enoxaparin and had steady-state antifactor Xa peak levels collected between April 2009 and April 2015. Institutional review board approval was obtained to collect data from patients' medical records. The primary outcome was the proportion of patients whose steady-state antifactor Xa peak levels were in the therapeutic, subtherapeutic, or supratherapeutic ranges. The secondary outcome was the incidence of major bleeding. Results: The final analysis showed that 63% of patients (n=47) had therapeutic levels, 22% (n=17) had subtherapeutic levels, and 15% (n=11) had supratherapeutic levels. No major bleeding incidents identified in the study. Conclusion: Based on the results of this study, monitoring antifactor Xa levels is warranted to ensure the safety and efficacy of renally adjusted doses of therapeutic enoxaparin in non-dialysis patients with severe renal impairment.