Clinical outcomes associated with anti‐Xa‐monitored enoxaparin for venous thromboembolism prophylaxis

Abstract

Study ObjectiveThe objective of the study was to assess clinical outcomes (composite of any venous thromboembolism [VTE], any bleeding, and mortality) associated with anti‐Xa monitoring in the 30 days following enoxaparin initiation for VTE prophylaxis.DesignRetrospective cohort study.SettingHospital within an academic healthcare system.PatientsPropensity score‐matched hospitalized adults receiving enoxaparin for VTE prophylaxis.InterventionLow‐molecular‐weight heparin anti‐Xa monitoring.Measurements and Main ResultsDuring the 13‐month study period, a total of 6611 patients received enoxaparin for VTE prophylaxis, 301 in the anti‐Xa monitored group and 6310 in the unmonitored group (4.6% received monitoring). The mean age was 52.9 years and 52% of patients were male. The mean body mass index was 31 kg/m2 and the mean creatinine clearance was 109 mL/min. Twenty percent of patients had active cancer. The most common indication for enoxaparin prophylaxis was hospitalization for medical illness (52%) followed by nonorthopedic surgery (37%). The adjusted odds ratio for the primary outcome comparing monitored to unmonitored patients was 1.26 (95% confidence interval, 0.75–2.11). None of the between‐group differences in the individual components of the composite outcome were statistically significant.ConclusionsThirty‐day clinical outcomes in patients receiving enoxaparin for VTE prophylaxis were not improved by anti‐Xa monitoring. Our results support current evidence‐based guideline recommendations against anti‐Xa monitoring for patients receiving enoxaparin for VTE prophylaxis.