MATERIALS AND METHODS: A systematic search of the literature was conducted on electronic databases of PubMed/MEDLINE, EBSCO, Cochrane library, Google, and Google Scholar from January 2011 to April 2021 to determine studies that reported warfarin adherence on patients with atrial fibrillation.

RESULTS: Out of 1429 titles and abstracts were retrieved, 12 studies fulfilled and met the inclusion criteria. From the included studies, two were carried out in Brazil and one from the following nations: Libya, Jordan, Iran, KSA, Canada, Malaysia, Bahrain, UAE, Singapore, and the USA. The study designs identified were cross-section, retrospective, and prospective studies. Warfarin adherence was influenced by multiple causes, including pharmaceutical services, the number of medications, and warfarin knowledge regarding anticoagulation control. Warfarin adherence illustrates its positive association with TTR and INR as a measure of anticoagulation control.