UMMS Affiliation

Department of Quantitative Health Sciences

Publication Date

9-10-2014

Document Type

Article

Disciplines

Endocrine System Diseases | Endocrinology, Diabetes, and Metabolism | Health Services Research

Abstract

Background and aim. Thyroid diseases are prevalent and chronic. With treatment, quality of life is restored in most, but not all patients. Construct validity of the thyroid-related quality of life questionnaire, ThyPRO, has been established by multi-trait scaling, but not evaluated with more elaborate methods. The purpose of the present study was to evaluate dimensionality of the ThyPRO scales and to attempt to understand possible item misfit through structural equation modeling for categorical data.

Methods. The current 84-item version of ThyPRO consists of 13 scales, covering domains of physical (4 scales) and mental (2 scales) symptoms, function and well-being (3 scales) and participation/social function (4 scales). The data were collected from a cross-sectional sample of 907 thyroid patients. One-factor confirmatory models were fitted to each scale, and evaluated by model fit statistics (comparative fit index > 0.95, root mean square error of approximation < 0.08), magnitude of factor loadings, model residual correlations and modification indices (MI). Indications of multi-dimensionality were tested in bi-factor models. Possible item misfit was evaluated in a combined, investigational model.

Results. Each ThyPRO scale was adequately represented by a unidimensional model after minor revisions. Eleven items were identified in the unidimensional models as potentially misfitting and were investigated further by multidimensional modeling.

Conclusion. Elaborate psychometric modeling supported the construct validity of the ThyPRO. However, 11 potentially misfitting items and 18 items with local dependence to other items are candidates for removal in future item reduction processes.

Rights and Permissions

Citation: Health Qual Life Outcomes. 2014 Sep 10;12(1):126. Link to article on publisher's site

DOI of Published Version

10.1186/s12955-014-0126-z

Related Resources

Link to Article in PubMed

Journal/Book/Conference Title

Health and quality of life outcomes

PubMed ID

25213857

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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