Title:
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Validation of the "World Health Organization Disability Assessment Schedule, WHODAS-2" in patients with chronic diseases
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Author:
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Garin Boronat, Olatz, 1979-; Ayuso Mateos, José Luis; Almansa, Josué; Nieto, Marta; Chatterji, Somnath; Vilagut Saiz, Gemma, 1975-; Alonso Caballero, Jordi; Cieza, Alarcos; Svetskova, Olga; Burger, Helena; Racca, Vittorio; Francescutti, Carlo; Vieta, Eduard; Kostanjsek, Nenad; Raggi, Alberto; Leonardi, Matilde; Ferrer Forés, Maria Montserrat; MHADIE consortium
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Abstract:
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Background: The WHODAS-2 is a disability assessment instrument based on the conceptual framework of the International Classification of Functioning, Disability, and Health (ICF). It provides a global measure of disability and 7 domain-specific scores. The aim of this study was to assess WHODAS-2 conceptual model and metric properties in a set of chronic and prevalent clinical conditions accounting for a wide scope of disability in Europe. Methods: 1,119 patients with one of 13 chronic conditions were recruited in 7 European centres. Participants were clinically evaluated and administered the WHODAS-2 and the SF-36 at baseline, 6 weeks and 3 months of follow-up. The latent structure was explored and confirmed by factor analysis (FA). Reliability was assessed in terms of internal consistency (Cronbach's alpha) and reproducibility (intra-class correlation coefficients, ICC). Construct validity was evaluated by correlating the WHODAS-2 and SF-36 domains, and comparing known groups based on the clinical-severity and work status. Effect size (ES) coefficient was used to assess responsiveness. To assess reproducibility and responsiveness, subsamples of stable (at 6 weeks) and improved (after 3 moths) patients were defined, respectively, according to changes in their clinical-severity. Results: The satisfactory FA goodness of fit indexes confirmed a second order factor structure with 7 dimensions, and a global score for the WHODAS-2. Cronbach's alpha ranged from 0.77 (self care) to 0.98 (life activities: work or school), and the ICC was lower, but achieved the recommended standard of 0.7 for four domains. Correlations between global WHODAS-2 score and the different domains of the SF-36 ranged from -0.29 to -0.65. Most of the WHODAS-2 scores showed statistically significant differences among clinical-severity groups for all pathologies, and between working patients and those not working due to ill health (p < 0.001). Among the subsample of patients who had improved, responsiveness coefficients were small to moderate (ES = 0.3-0.7), but higher than those of the SF-36. Conclusions: The latent structure originally designed by WHODAS-2 developers has been confirmed for the first time, and it has shown good metric properties in clinic and rehabilitation samples. Therefore, considerable support is provided to the WHODAS-2 utilization as an international instrument to measure disability based on the ICF model. |
Abstract:
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This study has been supported by the EC contract number SP24-CT-2004-513708 (MHADIE); by the Spanish Ministry of Health ISCIII FEDER (PI 061579, PI 051542, PI050036, and PI050206), CIBERSAM, CIBERESP, RETICS RD06/0011 (REM-TAP) and the Catalan Government DURSI-GENCAT (2005-SGR-00491), and AGAUR (2008FIC 00335). |
Subject(s):
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-Malalties cròniques -Qualitat de vida |
Rights:
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© 2010 Garin et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
http://creativecommons.org/licenses/by/2.0 |
Document type:
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Article Article - Published version |
Published by:
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BioMed Central
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