Assessment of psychometric properties of the Brazilian version of the oral anticoagulation knowledge test.

Marcus Fernando Da Silva Praxedes,Mauro Henrique Nogueira Guimarães De Abreu,Juliana Vaz De Melo Mambrini,Milena Soriano Marcolino,Saul Martins Paiva,Maria Auxiliadora Parreiras Martins

doi:10.1186/s12955-016-0498-3

Marcus Fernando Da Silva Praxedes, Mauro Henrique Nogueira Guimarães De Abreu + Show 4 more

Open Access

https://doi.org/10.1186/s12955-016-0498-3

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Abstract

BackgroundThe aim of this study was to evaluate the psychometric properties of the Brazilian version of the Oral Anticoagulation Knowledge (OAK) Test.MethodsThis study, conducted in an anticoagulation clinic, included 201 Brazilian participants aged over 18 years, who had been using warfarin for more than two months. The reliability of the instrument was evaluated by assessing internal consistency (Kuder-Richardson coefficient) and reproducibility (test-retest reliability). The validity was evaluated by hypothesizing that there would be a positive correlation of moderate to strong intensity between the correctness levels of the OAK Test and time within therapeutic range (TTR) values, which is a measure used to evaluate the quality of oral anticoagulation.ResultsThe instrument exhibited good psychometric properties. The total a Kuder-Richardson coefficient value was 0.818 and intraclass correlation coefficient was 0.967. The validity revealed a strong positive correlation between the values of the level of knowledge, as measured by the OAK Test and the TTR values (rs = 0.780).ConclusionThe instrument proved to be a reliable and valid tool for evaluating the knowledge of Brazilian patients on oral anticoagulation therapy with warfarin. This instrument may be incorporated into the practice of health care for substantiating the structuring of educational activities to ensure the improvement of knowledge about the use of warfarin, thereby increasing the effectiveness and safety of treatment.

Highlights

The aim of this study was to evaluate the psychometric properties of the Brazilian version of the Oral Anticoagulation Knowledge (OAK) Test
To evaluate the quality of anticoagulant therapy, the percentage of time of International Normalized Ratio (INR) in the therapeutic range is calculated, the bleeding and mortality rates being significantly higher in Praxedes et al Health and Quality of Life Outcomes (2016) 14:96 patients with TTR values 75 % [7]
60 of these patients were randomly selected for a new interview that was conducted within two to three months after the first interview, a period equal to that used in the study in which the original version of the OAK Test was developed [8]

Summary

Introduction

The aim of this study was to evaluate the psychometric properties of the Brazilian version of the Oral Anticoagulation Knowledge (OAK) Test. Warfarin is an oral anticoagulant, coumarinic derivative used worldwide for primary and secondary prophylaxis of thromboembolism. The indication of oral anticoagulation is increasing due to population aging and the consequent increase in the incidence of thromboembolic diseases [1,2,3,4,5]. Subtherapeutic results were related to the occurrence of venous thromboembolism and higher values, to increased risk of bleeding [1]. To evaluate the quality of anticoagulant therapy, the percentage of time of INR in the therapeutic range is calculated (time within therapeutic range; TTR), the bleeding and mortality rates being significantly higher in Praxedes et al Health and Quality of Life Outcomes (2016) 14:96 patients with TTR values 75 % [7]

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