Assessment of Anticoagulation Control Association with Warfarin Knowledge and Demographic Features of Iranian Population

Abstract

Background: Warfarin is the most commonly used oral anticoagulant for patients with atrial fibrillation, prosthetic heart valves, and deep vein thrombosis with a narrow therapeutic index. Due to the importance of patients’ adherence to treatment and also regular measurements of International normalized ratio (INR), this can have a significant impact on the quality of anticoagulation control. Objectives: The primary aim of this study was to assess the association between warfarin knowledge and time in therapeutic range (TTR) in patients on warfarin anticoagulation for at least 6 months who were referred to anticoagulation clinic in Rajaie Heart Center during 2016 - 2017. Methods: In this cross-sectional study, 620 patients who had been referred to the outpatient Rajaie Hospital anticoagulant clinic and had been taking warfarin for over six months were asked to fill two questionnaires named anticoagulation knowledge assessment (AKA) during a 12-week period. After obtaining the necessary permits, TTR (by Rosendal method) was calculated using the INR results of patients. Results: A total of 620 patients completed the questionnaire. The relation between warfarin knowledge and anticoagulation control was not significant. The mean age of the study population was 52.45 SD ± 14.01 years. This study showed a significant relationship between TTR, duration of warfarin usage (PV = 0.03) and the underlying cause of this usage (PV = 0.016). Conclusions: Prevention of chronic diseases is one of the most important priorities of the health care systems. Reduction in complications such as thrombosis and bleeding can be achieved by efforts to promote patient’s knowledge. By recognition of relation between warfarin knowledge and social and demographic indicators, patient’s education gap can be detected and also planned for dissolving. This study showed that although many of the patients visited in anticoagulation clinic have poor anticoagulation control, but a major part of them have good knowledge of warfarin usage.