[Development of the Spanish version of the KIDSCREEN, a health-related quality of life instrument for children and adolescents].

AIMS: To describe the cross-cultural development and psychometric properties of the Spanish version of the KIDSCREEN questionnaire, a health related quality of life instrument (HRQL) for use in children and adolescents aged 8-18 years old. The questionnaire was cross-culturally developed in 13 European countries.
METHODS: A literature review and Delphi study were performed, allowing consensus to be reached on the instrument's contents and structure. More specific items and dimensions were generated in focus groups. Forward and back translation and cultural adaptation were carried out, together with a pre-test (cognitive debriefing) to select items that were acceptable in all the countries involved. A pilot study was performed to obtain the definitive version of the KIDSCREEN through Rasch analysis and preliminary information on the questionnaire's psychometric properties.
RESULTS: The focus groups generated 1642 possible items, which were reduced during the stages of translation-adaptation and pilot study. The definitive version of the questionnaire contains 52 items and 10 dimensions. In the Spanish version, there was less than 5% nonequivalence (acceptability) in any of the dimensions, floor and ceiling effects were acceptable, and all dimensions had Cronbach's alpha values of > 0.70 (internal consistency).
CONCLUSIONS: The KIDSCREEN is the first HRQL instrument for children and adolescents to be developed simultaneously in several countries. The preliminary psychometric properties of the Spanish version were acceptable.