Non-Clinical Factors Associated with International Normalized Ratio Control in Patients on Warfarin Therapy: A Review Paper

Tharani Ramasamy, Naganathan Kathiresan Pillai, Christina Gertrude Yap, Nowrozy Kamar Jahan

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Warfarin is a coumarin derivative oral anticoagulant with a narrow therapeutic international normalized ratio (INR) range. Regular and accurate INR monitoring is essential for optimal anticoagulation management and to reduce the risk of adverse events. However, achieving and maintaining the therapeutic INR range are still a challenge as it is affected by several clinical and non-clinical factors. In this review paper, we analyzed how the non-clinical factors like socio-demographic, modifiable risk and protective factors affect the INR control in patients receiving warfarin therapy. We conducted an extensive literature search in Pubmed, Embase, Scopus and Web of Science for original articles or review papers published from 2016 to 2020. Finally, we included 20 articles in this review which fulfilled the selection criteria. Multiple factors such as female gender, ethnicity difference, lower education level, living alone, activities of daily living dependency, smoking, alcohol abuse, fasting and low body mass index along with poor access to medical facilities are associated with poor INR control. Patient self-management and weight elevation are known to be protective factors against poor INR control. Physicians managing patients on warfarin therapy are encouraged to identify and recognize these factors before prescribing warfarin to achieve and maintain the therapeutic INR.
Original languageEnglish
Article numbere6947
Number of pages21
JournalOpen Access Library Journal
Publication statusPublished - 27 Nov 2020


  • Non-Clinical, Risk Factor, International Normalized Ratio, Control, Warfarin

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