Influence of polymorphisms in CYP2C9, VKORC1, MDR1 and APOE genes on the warfarin maintenance dose in Brazilian patients

Background: Polymorphisms in the CYP2C9, VKORC1, MDR1 and APOE genes may impact warfarin dose. Aim: To investigate the influence of sociodemographic, clinical factors and polymorphisms *1, *2 and *3 for CYP2C9, -1639G>A for VKORC1, 3435C>T for MDR1, and ϵ2, ϵ3 and ϵ4 for APOE genes on the mean weekly warfarin maintenance dose in adults. Methods: This cross-sectional study recruited a calculated sample of 315 patients in three anticoagulation clinics in Brazil. A model containing the variables significantly associated with warfarin dose was estimated. Results: The mean age of patients was 64.1 ± 13.1 years, with 173 (54.9%) women. Age, use of amiodarone, genotype VKORC1 GA, genotype VKORC1 AA, genotypes CYP2C9*1/*2 or *1/*3 and genotypes CYP2C9*2/*2 or *2/*3 or *3/*3 were associated with a reduced warfarin dose. Conclusion: This study pointed out factors that could impact the management of oral anticoagulation.

Assessment of oral anticoagulation control at two pharmacist-managed clinics in Brazil

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.