Methods: This descriptive study included 114 patients (56 males, 58 females; mean age 53.0±13.5 years; range 18 to 80 years) who received warfarin therapy for at least three months at the Department of Cardiovascular Surgery of Ege University Medical Faculty Hospital between 4 October 2012 and 30 May 2013. Patients who agreed to participate in the study were older than 18 years of age and literate. Data were collected by using sociodemographic profiles and a questionnaire form on knowledge of and adherence to warfarin therapy. A score of 1 (one) was given to patients’ correct answers, and 0 (zero) was given to incorrect or “I don’t know” answers for each item on the scale, and mean scores were obtained. Patients’ adherence to warfarin was measured by four questions involving (i) regular use of the medication as prescribed by doctors, (ii) forgetting to take the medication, (iii) delaying for more than 24 hours, and (iv) frequency of overuse. The answers to these four questions were evaluated based on a 100 mm visual analog scale.

Results: Patients’ mean score regarding anticoagulant therapy was 9.8±3.9 (lowest: 2, highest: 20) out of 22. Of the patients, 62.3% (n=71) stated that they used warfarin precisely as prescribed by doctors (100%).

Conclusion: It was determined that patients with mechanical heart valve and using warfarin had low level of knowledge regarding warfarin therapy and that they experienced problems in terms of their adherence to the medication.