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Página 125 SUMMARY
This PhD Thesis was originated by the need and social demand of a Health Related Quality of Life (HRQoL) instrument that allows both, the analysis of health status and the development of economics utilities in children and adolescents. EuroQol foundation promotes the adaptation of the questionnaire EQ-5D (one of the most used HRQoL questionnaires in international studies with adults and elderly) for its use in children and adolescents. For it they established a specific Task Force formed by international experts in HRQoL who developed a first international version of the EQ-5D adapted for children and adolescents. This first version was the base for the development of the national versions for Germany, Italy, South Africa, Spain and Sweden. The development of the Spanish version is the first step of this PhD Thesis.
Furthermore in this task force were proposed and discussed the methodological guides for the development and validation of this new questionnaire which was named EQ-5D-Y (EQ-5D-Youth). This document shows the process of Spanish translation and cultural adaptation of the EQ-5D-Y, the analysis of its psychometric properties and the comparison between EQ-5D and EQ-5D-Y analyzing the age-appropriateness of both questionnaires.
The Spanish version of the EQ-5D-Y was developed from the original English by direct and indirect translation method. Once the Spanish
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version of EQ-5D-Y was obtained, its comprehensibility was analyzed by cognitive interviews with children and adolescents. With this method it was possible to adjust the Spanish EQ-5D-Y version facilitating the comprehensibility of this questionnaire.
The psychometric properties of the Spanish EQ-5D-Y in general population were later analyzed with the participation of 973 children and adolescents aged 8 to 17 years old. There was analyzed the convergent validity using Pearson or Spearman correlations (depending of variables characteristics) between EQ-5D-Y dimensions and other generic HRQoL measures. Additionally there was realized the Known groups validation method using Chi square analysis. The reliability was analyzed using test-retest method using the Kappa coefficient and percentage of agreement.
Results show the EQ-5D-Y is understandable and reliable for children and adolescents aged 8 to 17 years old in general population.
There were not lost data so this questionnaire showed to be applicable for the HRQoL evaluation in children and adolescents.
In some dimensions of EQ-5D-Y the percentage of reported problems was very low obtaining a high ceiling effect. It has affected negatively to the power of obtained results.
The EQ-5D-Y has shown a high reliability in all dimensions according to the percentage of agreement between test and retest. However, the low percentage of reported problems has affected to the Kappa coefficient in some dimensions.
SUMMARY AND CONCLUSIONS
Página 127 Referent to convergent validity, we have obtained some association models between EQ-5D-Y and others specific HRQoL instruments for children and adolescents and differences in HRQoL level between known groups. However new studies are needed analyzing the EQ-5D-Y validity in children and adolescents with special characteristics or specific pathologies where the ceiling effect is lower.
In conclusion the Spanish version of EQ-5D-Y is understandable and applicable for children and adolescent in general population. Results of this PhD thesis show the preliminary validity and reliability of this instrument in general population. New studies are needed analyzing the psychometrics properties of the EQ-5D-Y in population with special characteristics or specific pathologies.
AIMS
The overall aim of this PhD Thesis was to develop the Spanish version of questionnaire for the evaluation of Health Related Quality of Life in children and adolescents EQ-5D-Y, and to analyze its applicability and psychometrics properties in children and adolescents in general population.
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To achieve this aim there were formulated the following
HYPOTHESES
1. The Spanish version of the EQ-5D-Y developed by direct and indirect translation is understandable for children and adolescents in general population.
2. The Spanish version of the EQ-5D-Y is reliable for children and adolescents in general population.
3. The Spanish version of the EQ-5D-Y is more sensitive for the evaluation of Health Related Quality of Life in children and adolescents than the original version for adults and elderly, the EQ-5D.
4. The Spanish version of the EQ-5D shows convergent validity with other Health Related Quality of Life measures for children and adolescents in general population.
SUMMARY AND CONCLUSIONS
Página 129 The results presented in this PhD Thesis, the development and validation of the Spanish version of the EQ-5D-Y for children and adolescents in general population, derived in the following
CONCLUSIONS
1. The final EQ-5D-Y version translated and culturally adapted to Spanish has shown to be comprehensive for children and adolescents aged 8 to 17 years old in general population.
2. The Spanish version of the EQ-5D-Y showed an acceptable reliability in some dimensions.
3. The new EQ-5D-Y questionnaire has shown to be more sensitive for children and adolescents aged 8 to 17 years old in general population than the original version for adults and elderly.
4. There was proved the convergent validity of some dimensions of the EQ-5D-Y and its Visual Analogue Scale.
5. Because of there was a low percentage of participants with Health Related Quality of Life problems, further studies are needed in special populations who report a higher percentage of problems than general populations, especially in Mobility and Self-care dimensions.
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LIST OF PUBLICATIONS
The following publications have derived from this PhD Thesis:
Articles in scientific journals indexed in JCR
1. Gusi N, Badia X, Herdman M, Olivares PR. [Translation and cultural adaptation of the Spanish version of EQ-5D-Y questionnaire for children and adolescents]. Atención Primaria. 2009 Jan;41(1):19-23.
2. Ravens-Sieberer U., Wille N., Badia X., Bonsel G., Burstrom K., Cavrini G., Devlin N.,. Egmar AC, Gusi N., Herdman M., Jelsma J., Kind P., Olivares PR., Scalone L. and Greiner W. Feasibility, reliability, and validity of the EQ-5D-Y: results from a multinational study. Quality of Life Research. 2010 Apr 17.
Libros o capítulos de libro
1. Gusi N, Olivares PR, Rajendram R. The EQ-5D health related quality of life questionnaire. In: Preedy VR, Watson RR, editors. Handbook of Disease Burdens and Quality of Life Measures. New York: Springer;
2009. p. 87-100.
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Página 131 Contributions in scientific congress
1. Gusi N, Badia X, Herdman M, Olivares PR. Translation and testing of a Spanish child-friendly version of EQ-5D and the appropriateness of the EQ-5D. EuroQol Group’s 23nd Plenary Meeting;
Barcelona (España) 2006.
2. Gusi N, Badia X, Herdman M, Olivares PR. Reproducibility and validation of the Spanish EQ-5D Child version and the appropriateness of the EQ-5D for adults and EQ Child version. EuroQol Group’s 24nd Plenary Meeting; Haige (Netherlands) 2007.
3. Gusi N, Olivares PR, Badía X, Morell JJ, Herdman M. La versión española del cuestionario EQ-5D (CY) para niños y adolescentes:
Innovación, posibilidades y limitaciones. IV Reunión de la Asociación Española de Pediatría de Atención Primaria. Cáceres (España). 2008
Ravens-Sieberer U., Wille N., Badia X., Bonsel G., Burstrom K., Cavrini G., Devlin N.,. Egmar AC, Gusi N., Herdman M., Jelsma J., Kind P., Olivares PR., Scalone L. and Greiner W. Feasibility, reliability and validity of the EQ-5D-Y: results from a multinational study. 16th Annual Conference of the International Society for Quality of Life Research. New Orleans (USA). 2010.