Prevalent etiologies of non-therapeutic warfarin anticoagulation in a network of pharmacist-managed anticoagulation clinics

Excerpt

Background Vitamin K antagonists, such as warfarin, have been the cornerstone of anticoagulation therapy for several decades for many indications as described by the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy. Despite warfarin’s proven therapeutic success, there are limitations in clinical use including a narrow therapeutic index, and a pharmacokinetic profile which may be influenced by many environmental, disease, drug, food, and herbal interactions. For an anticoagulation care provider, it is important to recognize the prevailing causes of non-therapeutic anticoagulation episodes, in order to identify target areas for educational interventions and maximize the time in therapeutic range. A previous study by Wittkowsky and Devine defined the absolute frequency of several non-therapeutic etiologies in a primarily Caucasian, university-based clinic, but there have been no follow up investigations in the literature to evaluate if these results translate to all clinical settings. Objective To determine the prevailing etiologies of non-therapeutic warfarin anticoagulation episodes among patients currently enrolled in an anticoagulation clinic and compare the relative frequency in which they occur compared to therapeutic anticoagulation regimens. Secondarily, correlations between patient demographic information and non-therapeutic anticoagulation etiologies will be explored. Methods Prospective documentation of all patients enrolled in three pharmacist-managed anticoagulation clinics that arrive for office appointments during the 6-month time period from September 2006 to March 2007. Etiologies linked to the non-therapeutic INR values will be evaluated for absolute frequency, relative frequency compared to the therapeutic INR values, association with various demographic factors, and degree of variance away from the therapeutic range. Results will be available for presentation at the 9th National Conference on Anticoagulant Therapy. …