An observational evaluation of inpatient warfarin utilization and management

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Background Warfarin management presents significant challenges and its safe use has been the recent focus of various national regulatory organizations. In particular, the Joint Commission has proposed performance measures involving the treatment of venous thromboembolism (VTE) in an acute setting. This evaluation assessed inpatient warfarin utilization and management at our institution. The goal was to assess warfarin therapy in patients being treated for VTE and to assess the overall safe use of warfarin. Methods A retrospective, observational chart review was conducted for all patients >18 years of age, receiving ≥1 dose of warfarin during hospital admission in April and September 2006. Appropriate management decisions were assessed based on institutional anticoagulation medication guidelines. A patient specific bleeding risk was assigned to all patients based on co-morbidities and a composite endpoint (documented bleed in-house, documented transfusion with ≥2 units pRBC or FFP or decrease in Hgb by ≥2 g/dl) was used to assess bleeding outcomes. Results A total of 349 patient charts were reviewed and 31.8% of all warfarin treatment decisions were deemed inappropriate. One third of all patients classified as high risk, experienced a composite bleeding endpoint. A documented bleed was reported in 13% of all new warfarin starts during admission. Warfarin therapy was initiated in 47 patients for the treatment of VTE and of those patients, an inappropriate initial dose was associated with double the rates of documented bleeds and an increased use of vitamin K compared to those that were initiated appropriately. Upon discharge, 57% of patients treated for VTE had an INR <1.8 with only 70% of those patients discharged on a bridge therapy. No discharge instructions or plan for anticoagulation follow up was documented for 29% of patients. Conclusion The results highlight the general inappropriate management of warfarin among our inpatient population, in particular those patients treated for VTE. Pharmacist- directed management of warfarin in acute care settings has demonstrated a decreased length of stay, reduced bleeding complications and a reduction in hospital costs. Pharmacist involvement can maximize effectiveness while minimizing risks associated with warfarin use. A pharmacy-directed warfarin management service to target VTE patients or high-risk patients is being planned for implementation at our institution. …