Development of the Warfarin Knowledge Test in Patients Receiving Warfarin at Pathumthani Hospital

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Pornsiri Udomdachanut
Apiruk Wongruttanachai
Itsarawan Sakunrag


Background and ObjectiveAssessing patient’s knowledge on warfarin therapy is one of the key strategies for anticoagulation management. It helps pharmacist to identify patient’s knowledge deficits that can lead to improve the efficacy and safety of anticoagulation therapy. The objectives of this study aimed to develop a warfarin knowledge test for patient to complete the questionnaires at the clinic and to validate the quality of test in aspects of content validity, item difficulty, item discrimination, reliability and construct validity.

MethodResearch and development study including 2 steps: First step was to construct and develop a warfarin knowledge test using 6 experts. Step 2 was to validate the quality of a test. Warfarin knowledge test was administered to two groups of participants comprising of 67 patients who were taking warfarin at Pathumthani hospital and 100 general public. Item difficulty and item discrimination, reliability and construct validity were analyzed by using Brennan Index, Lovette, and Carver methods, respectively.

ResultThirty multiple-choice questionnaires of warfarin knowledge test for patients to complete at the clinic had item content validity index between 0.83-1.00, the difficulty index between 0.20-0.90, the discrimination index between 0.20-0.80 with the reliability of 0.76 and the construct validity of 0.76.

Conclusion:  The results shows that the developed warfarin knowledge test has acceptable level of quality for self-assessing the patient’s knowledge in routine clinical practice


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