Enoxaparin dosing and associated risk of in-hospital bleeding and death in patients with non-ST-segment elevation acute coronary syndromes

Background: The efficacy of enoxaparin sodium in non ST-segment elevation acute coronary syndromes is well established; however, concerns remain regarding bleeding risk. The extent to which bleeding risk is attributable to excess dosing of enoxaparin is unclear. Methods: Using data from the CRUSADE (Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes With Early Implementation of the ACC/AHA Guidelines) National Quality Improvement Initiative, we determined the frequency of administration of excess (> 10 mg above the recommended dose), lower-than-recommended (> 10mg below the recommended dose), and recommended doses of enoxaparin. We also determined unadjusted and adjusted risks of in-hospital major bleeding and death associated with excess and lower-than-recommended doses of enoxaparin. Results: Of 10 687 patients, 2002 (18.7%) received an excess dose and 3116 (29.2%) received a lower-than-recommended dose of enoxaparin. Patients receiving excess doses were older (median age, 78 vs 66 years), smaller (median body mass index [calculated as weight in kilograms divided by height in meters squared], 26.2 vs 27.8), and more likely to be female (59.5% vs 38.2%) than patients receiving recommended doses (P <. 001 for all). After adjustment for baseline characteristics, an excess dose was significantly associated with major bleeding (odds ratio, 1.43; 95% confidence interval [CI], 1.18-1.75) and death (odds ratio, 1.35; 95% CI, 1.03-1.77) compared with a recommended dose. A lower-than-recommended dose was not associated with major bleeding (odds ratio, 1.01; 95% CI, 0.84-1.21), but there was a trend toward higher mortality (odds ratio, 1.25; 95% CI, 0.93-1.68). Conclusions: Almost half the patients treated with enoxaparin did not receive a recommended dose and had worse outcomes, especially those receiving an excess dose. Improved adherence to the recommended dose could substantially improve the safety profile of enoxaparin.