Objective: To describe the cross-cultural adaptation of the questionnaire evaluating adhesion to treatment for arterial hypertension from its original Spanish version to a Portuguese version, to be applied in Brazil.
Methods: In order to establish conceptual, semantic and operational equivalents of the items, two independent translations to Portuguese, and two back-translations into Spanish were performed. The translations and back-translations were assessed for changes in referential and general meanings. The synthesis of the translations was applied in pre-tests with patients with arterial hypertension and/or diabetes, which were important to identify different problems and confirm earlier decisions.
Results: In general, the second translation and back translation were evaluated more positively because the translation process did not affect the meanings in five of the twelve items of the questionnaire. Operational changes were made and a vignette with response options and an example included in the instrument facilitated application in interviews.
Conclusions: The results obtained in the process of evaluating the items' conceptual, semantic and operational equivalence allowed the construction of a Portuguese version of the MBG questionnaire to assess adherence to treatment which can be applied in the Brazilian context.