Cross-cultural validation of the Spanish version of the Kidney AlloTransplant Immunosuppressive Therapy Adherence Questionnaire (KATITA-25)

The KATITA-25 (Kidney AlloTransplant Immunosuppressive Therapy Adherence) Questionnaire is a multidimensional self-administered scale developed in Brazilian Portuguese that measures the predisposition for non-adherence to immunosuppressive medication in candidate patients for kidney transplantation, in the pre-transplant setting. The aim of this study was the cross-cultural validation of the Spanish version of the KATITA-25 scale. The translation/back-translation method was used, followed by cognitive interviews and a pre-test. The Spanish version of KATITA-25 was administered to 163 candidate patients for kidney transplantation from 2 kidney transplant centres and 2 dialysis centres in Catalonia, Spain. The scale was re-administered to the first 79 patients included into the study, after a 2 to 4 weeks interval. Internal consistency was assessed using Cronbach's alpha, test-retest reliability with the intraclass correlation coefficient (ICC); construct validity with goodness of fit indices after confirmatory factor analysis using structural equation modelling. The Cronbach's alpha of the Spanish version was 0.83, the ICC was 0.86. Confirmatory factor analysis showed adequate fit of the structural model. Overall, the analytical results closely resembled those obtained in the validation of the original scale. In conclusion, this cross-cultural validation study showed adequate reliability and construct validity of the Spanish version of the KATITA-25 questionnaire.