Torquil Watt1,2, Jakob Bue Bjorner3,4, Mogens Groenvold4,5, Per Cramon1, Kristian Hillert Winther6, Laszlo Hegedüs6, Steen Joop Bonnema6, Åse Krogh Rasmussen1, John E Ware7, Ulla Feldt-Rasmussen1. 1. 1 Department of Endocrinology, Copenhagen University Hospital Rigshospitalet , Copenhagen, Denmark . 2. 2 Department of Internal Medicine F, Gentofte Hospital , Denmark . 3. 3 OptumInsight , Lincoln, Rhode Island. 4. 4 Department of Public Health, University of Copenhagen , Copenhagen, Denmark . 5. 5 Department of Palliative Medicine, Bispebjerg Hospital , Copenhagen, Denmark . 6. 6 Department of Endocrinology and Metabolism, Odense University Hospital , Odense, Denmark . 7. 7 Department of Quantitative Health Sciences, University of Massachusetts Medical School , Worcester, Massachusetts.
Abstract
BACKGROUND: Thyroid diseases affect quality of life (QoL). The Thyroid-Related Patient-Reported Outcome (ThyPRO) is an international comprehensive well-validated patient-reported outcome, measuring thyroid-related QoL. The current version is rather long--85 items. The purpose of the present study was to develop an abbreviated version of the ThyPRO, with conserved good measurement properties. METHODS: A cross-sectional (N = 907) and a longitudinal sample (N = 435) of thyroid patients were analyzed. A graded item response theory (IRT) model was fitted to the cross-sectional data. Short-form scales with three items were aimed for, by selecting items with best fit according to the IRT model, avoiding cross-culturally noninvariant items. Seven scales measuring mental and social well-being and function as well as one overall QoL impact item were analyzed in a bifactor model, to develop a supplementary composite score. Short-form scales were linked to original scales with IRT-based summed-score-linking. Agreement between the short and long form was estimated by agreement plots, intraclass correlations, and mean score levels. Responsiveness was compared by relative validity indices, clinical validity by ability to detect clinically relevant differences, and test-retest reliability by intra-class correlation. RESULTS: One four-item scale was not abbreviated and one two-item scale was omitted from the short-form. For the 11 scales undergoing abbreviation, 10 with three and one with four items were developed. A bifactor model with good overall fit was fitted to the composite score, including the single QoL item. Responsiveness and clinical validity of the short-form scales were preserved, as were test-retest reliability (0.75-0.89). Short- versus long-form intraclass correlations were high (0.89-0.98), and the mean scale levels were similar. CONCLUSIONS: A 39-item version of the ThyPRO, with good measurement properties, was developed and is recommended for clinical use.
BACKGROUND:Thyroid diseases affect quality of life (QoL). The Thyroid-Related Patient-Reported Outcome (ThyPRO) is an international comprehensive well-validated patient-reported outcome, measuring thyroid-related QoL. The current version is rather long--85 items. The purpose of the present study was to develop an abbreviated version of the ThyPRO, with conserved good measurement properties. METHODS: A cross-sectional (N = 907) and a longitudinal sample (N = 435) of thyroidpatients were analyzed. A graded item response theory (IRT) model was fitted to the cross-sectional data. Short-form scales with three items were aimed for, by selecting items with best fit according to the IRT model, avoiding cross-culturally noninvariant items. Seven scales measuring mental and social well-being and function as well as one overall QoL impact item were analyzed in a bifactor model, to develop a supplementary composite score. Short-form scales were linked to original scales with IRT-based summed-score-linking. Agreement between the short and long form was estimated by agreement plots, intraclass correlations, and mean score levels. Responsiveness was compared by relative validity indices, clinical validity by ability to detect clinically relevant differences, and test-retest reliability by intra-class correlation. RESULTS: One four-item scale was not abbreviated and one two-item scale was omitted from the short-form. For the 11 scales undergoing abbreviation, 10 with three and one with four items were developed. A bifactor model with good overall fit was fitted to the composite score, including the single QoL item. Responsiveness and clinical validity of the short-form scales were preserved, as were test-retest reliability (0.75-0.89). Short- versus long-form intraclass correlations were high (0.89-0.98), and the mean scale levels were similar. CONCLUSIONS: A 39-item version of the ThyPRO, with good measurement properties, was developed and is recommended for clinical use.
Authors: Honghu Liu; Ron Hays; Yan Wang; Marvin Marcus; Carl Maida; Jie Shen; Di Xiong; Steve Lee; Vladimir Spolsky; Ian Coulter; James Crall Journal: Qual Life Res Date: 2018-03-05 Impact factor: 4.147
Authors: Yan Wang; Ron Hays; Marvin Marcus; Carl Maida; Jie Shen; Di Xiong; Steve Lee; Vladimir Spolsky; Ian Coulter; James Crall; Honghu Liu Journal: Int J Paediatr Dent Date: 2019-01-24 Impact factor: 3.455
Authors: A E Zahan; T Watt; I Pascanu; A K Rasmussen; L Hegedüs; S J Bonnema; U Feldt-Rasmussen; J B Bjorner; V Nadasan; A Boila; I Merlan; A Borda Journal: Acta Endocrinol (Buchar) Date: 2018 Apr-Jun Impact factor: 0.877