Decreased Kidney Function Increases Bleeding Risk with Enoxaparin

Patients with moderate renal impairment have a sharply increased risk of major bleeding during treatment with enoxaparin, suggests a report in the Archives of Internal Medicine.

From June through November 2009, 164 patients at the authors’ Veterans Administration medical center were treated with enoxaparin sodium (1 mg/kg every 12 hours or 1.5 mg/kg once daily). On the basis of a creatinine clearance of 30–50 mL/min, 59 patients were classified as having moderate renal impairment. Episodes of major bleeding—causing death, hospitalization, longer hospital stay, or emergency department visit—were compared for patients with moderate renal impairment versus normal renal function (creatinine clearance over 80 mL/min).

Twenty-two percent of patients with moderate renal impairment had major bleeding episodes while taking enoxaparin, compared with 5.7 percent of those with normal renal function. The odds ratio for major bleeding in the moderate renal impairment group was 4.7, decreasing to 3.9 on multivariable adjustment for other risk factors. Independently of renal function, the risk of major bleeding was higher in patients receiving enoxaparin as bridge therapy: 13.7 percent, compared with 8.1 percent for those receiving new anticoagulation. Thromboembolism, evaluated as a secondary outcome, was similar between groups.

Enoxaparin, a low-molecular-weight heparin, allows simplified dosing without the need for laboratory monitoring. Even though enoxaparin is excreted by the kidneys, there is no recommended dose adjustment for patients with moderate renal impairment.

This study finds a fourfold increase in major bleeding with enoxaparin in patients with moderate renal impairment. More research is needed to establish appropriate dosing of this important and widely used anticoagulant in patients with reduced kidney function [DeCarolis DD, et al. Enoxaparin outcomes in patients with moderate renal impairment. Arch Intern Med 2012; 172:1713–1718].

February 2013 (Vol. 5, Number 2)