Variability of Antithrombotic Dosing Among Veterans Presenting With Acute Coronary Syndrome

Background Antithrombotic therapy for acute coronary syndrome (ACS) patients is recommended by clinical practice guidelines. Appropriate dosing of antithrombotic therapy is necessary to ensure effectiveness and safety and is an American College of Cardiology/American Heart Association ST elevated myocardial infarction/non‐ST elevated myocardial infarction performance measure. This study describes the variability in dosing of unfractionated heparin (UH) and low‐molecular‐weight heparin (LMWH) in an integrated health care system with electronic medical records and computerized physician order entry (CPOE). Methods and Results This was a mixed‐methods study of veterans presenting with ACS at 135 Veterans Health Administration hospitals from 2009 to 2011. Patients hospitalized with ACS and received antithrombotic therapy were included (n=36 682). The cohort was 98% male with an average age of 66 years and median body mass index (BMI) of 28.6. The average percentage of patients by hospital who received an above‐recommended dose of either antithrombotic was 7.5% and ranged 0% to 32.0%. By individual therapy, the average percentage of patients by hospital who received an above‐recommended dose of UH was 1.2% and LMWH was 12.9%. Risk‐adjusted analyses demonstrated that older age and higher BMI were associated with lower risk for receiving a dose above recommended levels. Additionally, there was an association between antithrombotic ordered by a resident and higher risk of the patient receiving an above‐recommended dose. Qualitative interviews supported the quantitative findings by highlighting the need to use current patient weight and the need to adequately train providers on the use of CPOE to improve antithrombotic dosing. Conclusion This study found wide hospital variability in dosing of antithrombotics above the recommended level for patients treated for ACS.