Abstract 349: Variability of Anticoagulant Dosing Among Hospitals for Patients Presenting with Acute Coronary Syndrome in the VA

Abstract

Background: Anticoagulant therapy for ACS patients is recommended by clinical practice guidelines. Further, appropriate dosing of anticoagulant therapy is necessary to ensure effectiveness and safety and is a current ACC/AHA STEMI/NSTEMI test performance measure. This study describes the variability in excess dosing of unfractionated heparin (UFH), low-molecular weight heparin (LMWH), and glycoprotein IIb/IIIa inhibitors among all VA hospitals and the association between patient, provider and facility characteristics with excessive dosing. Methods: This was a national cohort of 53,489 patients admitted for ACS at 135 VA hospitals between FY09-FY11 and administered anticoagulation therapy during their hospital stay. Excess dosing was defined based on the ACC/AHA test performance measures: unfractionated heparin > 70U/kg or infusion >15U/kg per hour, low molecular weight heparin (LMWH) >1.05mg/hr and glycoprotein IIb/IIa inhibitors, epifibitide: >180ug/kg and infusion of >2.0 ug/kg per minute among patients with creatinine clearance <50ml/min; tirofiban >0.4ug/kg and infusion of >0.1ug/kg among patients with creatinine clearance <30ml/min. Results: Dosing information was available in 39,873 (~75%) patients. Among these patients, 62.7% (25003) were prescribed unfractionated heparin, 34.9% (13919) were prescribed LMWH, and 2.4% (951) were prescribed glycoprotein IIb/IIIa. The average (standard deviation) percentage of patients receiving excess dosing of any anticoagulant at a hospital was 10.1% (12.2%); and 10.7% (20.9%) for unfractionated heparin, 12.9% (8.4%) for LMWH and 0.54% (1.9%) for glycoprotein IIb/IIIa. In general, common factors associated with excess dose across the three types of anticoagulants included older age, lower BMI, and higher serum creatinine. Among the provider and facility characteristics, anticoagulant dose ordered by an emergency department physician versus hospitalist, and first administered anticoagulant occurring in ICU versus not ICU were also associated with reduced risk of excessive dosing. Conclusions: There is wide hospital variability in excess dosing of anticoagulants for patients treated for ACS. Next steps include conducting qualitative interviews at sites to further understand reasons for variation in anticoagulant dosing. It will be important to incorporate both the identified factors associated with excessive dosing and the qualitative interview findings into future interventions to ensure appropriate dosing of anticoagulants for ACS patients.