Weight-based dosing of enoxaparin in obese patients with non-ST-segment elevation acute coronary syndromes: results from the CRUSADE initiative.

STUDY
OBJECTIVE: To evaluate how enoxaparin is dosed in contemporary clinical practice as a function of patients' total body weight (TBW) and body mass index (BMI), and to determine any association between dose and major bleeding.
DESIGN: Retrospective cohort study. DATA SOURCE: The Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the American College of Cardiology-American Heart Association Guidelines (CRUSADE) national quality improvement initiative database. PATIENTS: A total of 19,061 patients enrolled in the CRUSADE initiative between January 1, 2004, and March 31, 2006, who received enoxaparin for the initial treatment of non-ST-segment elevation acute coronary syndromes.
MEASUREMENTS AND MAIN RESULTS: Demographic and clinical data, enoxaparin doses, and frequency of major bleeding unrelated to coronary artery bypass graft (CABG) surgery were compared among patient groups stratified by TBW(< or = 100, 101-120, 121-150, and > 150 kg). Adjusted odds ratios (OR) of major bleeding unrelated to CABG surgery were calculated with each dose increase of 0.25 mg/kg stratified by BMI (< 18.5, 18.5-24.9, 25.0-29.9, and > or = 30 kg/m(2)), as well as for patients receiving a reduced dose (< 0.95 mg/kg) compared with those receiving a recommended dose (0.95-1.05 mg/kg), stratified by TBW. An inverse association was noted between enoxaparin dose and patient weight. Median initial doses were 1 mg/kg in those weighing 100 kg or less, 0.96 mg/kg in those 101-120 kg, 0.92 mg/kg in those 121-150 kg, and 0.65 mg/kg in those weighing more than 150 kg (p<0.0001 for < or = 100 kg vs > 150 kg). Up to 80% of patients weighing more than 150 kg received an initial enoxaparin dose below the recommended dose. In contrast to patients with normal body weight, those weighing more than 150 kg who received a recommended dose of enoxaparin had a higher bleeding risk relative to those who received a lower dose (adjusted OR 2.42, 95% confidence interval 0.70-8.37).
CONCLUSION: Clinicians tend to use reduced weight-based doses of enoxaparin in overweight and obese patients. Although data are limited, use of the recommended enoxaparin dose of 1 mg/kg is associated with a higher bleeding risk in those weighing more than 150 kg. Thus, further study of enoxaparin dosing in very obese patients with non-ST-segment elevation acute coronary syndromes is warranted.