Dosing practices and risk factors for bleeding in patients receiving enoxaparin for the treatment of an acute coronary syndrome.

OBJECTIVES To describe dosing practices and to identify risk factors for bleeding in patients with an acute coronary syndrome (ACS) who received treatment with enoxaparin. DESIGN Retrospective chart review. SETTING Coronary care unit of a tertiary-care teaching hospital. PATIENTS Patients with a discharge diagnosis of an ACS who received at least one dose of enoxaparin, 1 mg/kg, were eligible for this study. Enoxaparin dosing practices, factors that might influence the safety of enoxaparin administration, and bleeding events were documented. Multivariable regression analysis was used to identify independent predictors of bleeding in this clinical setting. RESULTS Of 208 patients with an ACS who received enoxaparin, 48 patients (23%) received a dose that was > 10% or < 10% of the recommended 1 mg/kg dose, 18 patients (9%) did not have body weight documentation to guide enoxaparin dosing, and 17 patients (8%) had significant renal impairment (serum creatinine > 150 micromol/L), with the potential for bioaccumulation of enoxaparin. There were 35 bleeding events (17%), of which 8 events (4%) were major. Risk factors for any bleeding (major or minor) were increasing patient age (odds ratio [OR], 1.57; 95% confidence interval [CI], 1.13 to 2.20), coadministered nonsteroidal anti-inflammatory or antiplatelet drug therapy (OR, 2.38; 95% CI, 1.06 to 5.38), and number of enoxaparin doses (OR, 2.15; 95% CI, 1.25 to 3.68). Risk factors for major bleeding were increasing patient age (OR, 2.56; 95% CI, 1.05 to 6.28) and coadministered clopidogrel (OR, 7.70; 95% CI, 1.16 to 51.9). CONCLUSION In this clinical practice assessment of patients with an ACS, the use of enoxaparin was suboptimal, with the potential to increase bleeding complications. Coadministered clopidogrel, other drugs that affect hemostasis, and increasing age conferred an increased bleeding risk.