[Validation of the Portuguese version of an instrument to measure the degree of patient knowledge about their medication]

Abstract

The scope of this study was the validation of a cross-culturally adapted questionnaire into Portuguese in five community pharmacies in Portugal. The discriminatory power of items, content and construct validity and factor analysis of the main components and their reliability and stability were determined. A high degree of semantic equivalence between the original questionnaire and the cross-culturally adapted questionnaire into Portuguese was observed. A Kaiser-Meyer-Olkin index of 0.550 was obtained and the Bartlett sphericity test confirmed the adequacy of the data for the application of factor analysis (p <0.0001). Three factors which accounted for 52.6% of the total variability were considered. With respect to reliability the following results were obtained: 0.519 for Cronbach's alpha test; 0.89 for Cohen's kappa coefficient; and 0.756 (IC=0.598-0.963) for the CCI exam. In this work, the first adaptation for the Portuguese culture of a specific questionnaire was produced to measure the degree of knowledge patients have about their medication.