Development, reliability testing and validation of the questionnaire for assessing patient knowledge about the impact of food on the efficacy of oral anticoagulants

Abstract

© 2018 Katarina V. Tomašević et al., published by Sciendo 2018. Oral anticoagulants, vitamin K antagonists (varfarin and acenocoumarol), are widely used for primary and secondary prevention of thromboembolic events. Previous studies have shown that patients had a low level of knowledge on warfarin, especially its interactions with food. The study was aimed at the development, reliability testing and validation of the questionnaire on patients' knowledge about the impact of food on the efficacy of oral anticoagulants. We performed a prospective study based on the development, validation and testing the reliability of the questionnaire on patient knowledge about the impact of food on the efficacy of oral anticoagulants. The study involved patients from the General Hospital Studenica in Kraljevo. The study included 226 subjects. The questionnaire consisted of 10 questions. Cronbach α coefficient, after the elimination of inappropriate questions, was 0.882. The questionnaire consisted of two factors which represent-ed 50.07% and 10.03% of the variance of the questionnaire. This is a unique, reliable and valid questionnaire that measures the level of patient knowledge on the impact of food on the efficacy of oral anticoagulants. Using this questionnaire, as an instrument, makes it possible to identify patients who use oral anticoagulants with insufficient knowledge about possible drug-food inter-actions.