Oral anticoagulation with coumarin derivatives (OAC) has been used for more than 50 years and is being prescribed to a steadily increasing number of patients as a long-term therapy. The aim of our study was to evaluate patients' knowledge about the safety of acenocumarol treatment, the therapeutic range of International Normalized Ratio (INR) and its interactions with other medications and food.
Material and methods: One hundred and forty patients on long-term acenocumarol treatment were included in the study. They were interviewed using a questionnaire specifically prepared by the authors. The questions concerned their understanding of the reasons for the treatment, knowledge of target INR ratio, frequency of INR examination. Additionally the questionnaire contained questions specifically designed to check the patients' knowledge about factors influencing INR values e.g. drugs, food, alcohol and the like.
Results: One hundred and fifteen (82.1%) patients declared knowledge of target INR ratio, but only eighty eight (62.9%) answered correctly. Percentages of correct answers for the questions evaluating knowledge about acenocumarol treatment did not exceed 50%. Patients' responses suggested that advice was not always provided by doctors.
Conclusions: Level of patients' knowledge about the safety of OAC treatment was very low. Insufficient knowledge was observed particularly in patients with lower education levels and those over 60 years of age. Those groups require a special attention and longer education to be able to self-manage the treatment. Special anticoagulant clinics do not exist in Poland. So, it seems very appropriate to develop concise guidelines available for patients in practices of family doctors. Education should be systematic and modified according to changing recommendations.