Impact of adherence to warfarin therapy during 12 weeks of pharmaceutical care in patients with poor time in the therapeutic range

Abstract

Poor adherence to warfarin treatment is a contributor to poor quality of treatment, which increases the risk of bleeding and thromboembolic events. This study aims to evaluate the impact of adherence to warfarin therapy on anticoagulation quality during 12 weeks of pharmaceutical care and after 1 year of follow-up for patients with atrial fibrillation and with poor TTR. The Arrhythmia Unit of tertiary hospital in Brazil. We included 262 patients with AF and poor quality of anticoagulation therapy with warfarin (TTR < 50%). Pharmacist-driven therapy management was performed for 12 weeks and patients were also evaluated 1 year after the end of the follow-up with a pharmacist. Adherence was classified into high adherence, medium adherence and low adherence. Impact of adherence to warfarin therapy after pharmaceutical care. Of the 262 patients, 160 were high adherence, 71 were medium adherence and 31 were low adherence. No statistically significant difference is found between adherence groups in demographic and clinical variables. The TTR basal means were not different among adherence groups (p = 0.386). However, the means of TTR 12 weeks and TTR 1 year after the end of protocol were statistically different among adherence groups (p < 0.001 and p = 0.002, respectively). When we compared TTR values at different times within the adherence group, we observed that there is a statistical difference between the three TTR means (basal versus 12 weeks versus 1 year after) within the adherence group (p < 0.001). Patients with poor anticoagulation control, who adhered to the treatment with warfarin during the pharmaceutical care had better anticoagulation quality compared to those who did not adhere to the therapy with warfarin.

Keywords: Adherence to warfarin; Atrial fibrillation; Management of adherence; Pharmaceutical care; Quality of anticoagulation; Time in the therapeutic range.