Cross-cultural adaptation and psychometric properties of the Brazilian-Portuguese version of the Duke Anticoagulation Satisfaction Scale.

AIM: The aim of this study was to evaluate the internal reliability and validity of the Brazilian-Portuguese version of Duke Anticoagulation Satisfaction Scale (DASS) among cardiovascular patients.

BACKGROUND: Oral anticoagulation is widely used to prevent and treat thromboembolic events in several conditions, especially in cardiovascular diseases; however, this therapy can induce dissatisfaction and reduce the quality of life.

DESIGN: Methodological and cross-sectional research design.

METHODS: The cultural adaptation of the DASS included the translation and back-translation, discussions with healthcare professionals and patients to ensure conceptual equivalence, semantic evaluation and instrument pretest. The Brazilian-Portuguese version of the DASS was tested among subjects followed in a university hospital anticoagulation outpatient clinic. The psychometric properties were assessed by construct validity (convergent, known groups and dimensionality) and internal consistency/reliability (Cronbach's alpha).

RESULTS: A total of 180 subjects under oral anticoagulation formed the baseline validation population. DASS total score and SF-36 domain correlations were moderate for General health (r=-0.47, p<0.01), Vitality (r=-0.44, p<0.01) and Mental health (r=-0.42, p<0.01) (convergent). Age and length on oral anticoagulation therapy (in years) were weakly correlated with total DASS score and most of the subscales, except Limitation (r=-0.375, p<0.01) (Known groups). The Cronbach's alpha coefficient was 0.79 for the total scale, and it ranged from 0.76 (hassles and burdens)-0.46 (psychological impact) among the domains, confirming the internal consistency reliability.

CONCLUSIONS: The Brazilian-Portuguese version of the DASS has shown levels of reliability and validity comparable with the original English version.

RELEVANCE TO CLINICAL PRACTICE: Healthcare practitioners and researchers need internationally validated measurement tools to compare outcomes of interventions in clinical management and research tools in oral anticoagulation therapy.