Translation, cross-cultural adaptation and psychometric evaluation of the Brazilian version of the Cystic Fibrosis Knowledge Scale (CFKS)

BACKGROUND: Information on the level of knowledge about cystic fibrosis (CF) among affected people and their families is still scarce. OBJECTIVE: This study aimed to translate, cross-culturally adapt and analyze the psychometric properties of the Brazilian version of Cystic Fibrosis Knowledge Scale (CFKS). MATERIALS AND METHODS: The translation and cross-cultural adaptation involved the stages of translation, synthesis of translations, reverse translation, synthesis of reverse translations, review by a multi-professional committee of experts and pre-testing. The reliability, viability, construct, predictive, concurrent and discriminant validity were investigated. RESULTS: The sample consisted of 40 individuals with cystic CF, 47 individuals with asthma, 242 healthcare workers and 81 students from the health area. The Brazilian version of the CFKS presented high internal consistency (α = 0.91), moderate floor and ceiling effects, without differences in the test-retest scores. An analysis of factorial exploration identified three dimensions. Confirmatory factor analysis led to an acceptable data-model fit. There was good predictive validity, with a difference in the scores among all the evaluated groups (p <0.001), as well as good discriminant validity since individuals with asthma had greater knowledge of asthma compared to CF (r = 0.401, p = 0.005; r(2) = 0.162). However, there was no difference between the diagnosis time and knowledge about CF (r = -0.25, p = 0.11; r(2) = 0.06), either between treatment adherence and knowledge about CF (r = -0.04, p = 0.77; r(2) = 0.002). CONCLUSION: The Brazilian version of the CFKS indicated that the scale is able to provide valid, reliable and reproducible measures for evaluating the knowledge about CF.