Background Warfarin remains widely used by patients with cardiovascular diseases. When using warfarin, the quality of oral anticoagulation control is a critical determinant to minimize the risk of bleeding and thromboembolic events. Pharmacist engagement in patient care is relevant towards improving the quality of warfarin therapy. Objective To assess the quality of oral anticoagulation control measured by time in therapeutic range (TTR) at two pharmacist-managed anticoagulation clinics (AC). Method This study included adults with indication of continuous warfarin use. Patients were recruited at two AC of public hospitals in Brazil (2014-2015). Anticoagulation control was assessed by TTR using the Rosendaal method. Laboratory INR values were collected for the maximum period of follow-up (2009-2015). Results A total of 554 patients were studied. The median age was 63.7 [Quartile 1 (Q1) 54.3; Quartile 3 (Q3) 73.6] years, 57.4% female. The median TTR was 64.3% [Q1 54.0%; Q3 74.0%], and 344 (61.6%) patients had TTR ≥ 60%. Conclusion Pharmacist-managed AC have achieved an adequate TTR in Brazilian patients with low socioeconomic status. Interventions include face-to-face appointments for individual patient education, warfarin-dosing adjustments and monitoring of drug interactions. Pharmacists are important to improve adherence and the quality of warfarin therapy in low- and middle income countries.
Keywords: Anticoagulants; Brazil; INN; International normalized ratio; Outpatient clinics; Pharmacists; Warfarin.