Aureliano Paolo Finch1, John Edward Brazier2, Clara Mukuria2, Jakob Bue Bjorner3. 1. Health Economics and Decision Science, School of Health and Related Research, University of Sheffield, Sheffield, UK. Electronic address: APFinch1@sheffield.ac.uk. 2. Health Economics and Decision Science, School of Health and Related Research, University of Sheffield, Sheffield, UK. 3. Health Economics and Decision Science, School of Health and Related Research, University of Sheffield, Sheffield, UK; Optum Insight, Eden Prairie, Minnesota, USA; Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark.
Abstract
OBJECTIVE: Generic preference-based measures such as the EuroQol five-dimensional questionnaire (EQ-5D) are used in economic evaluation, but may not be appropriate for all conditions. When this happens, a possible solution is adding bolt-ons to expand their descriptive systems. Using review-based methods, studies published to date claimed the relevance of bolt-ons in the presence of poor psychometric results. This approach does not identify the specific dimensions missing from the Generic preference-based measure core descriptive system, and is inappropriate for identifying dimensions that might improve the measure generically. This study explores the use of principal-component analysis (PCA) and confirmatory factor analysis (CFA) for bolt-on identification in the EQ-5D. METHODS: Data were drawn from the international Multi-Instrument Comparison study, which is an online survey on health and well-being measures in five countries. Analysis was based on a pool of 92 items from nine instruments. Initial content analysis provided a theoretical framework for PCA results interpretation and CFA model development. PCA was used to investigate the underlining dimensional structure and whether EQ-5D items were represented in the identified constructs. CFA was used to confirm the structure. CFA was cross-validated in random halves of the sample. RESULTS: PCA suggested a nine-component solution, which was confirmed by CFA. This included psychological symptoms, physical functioning, and pain, which were covered by the EQ-5D, and satisfaction, speech/cognition,relationships, hearing, vision, and energy/sleep which were not. These latter factors may represent relevant candidate bolt-ons. CONCLUSIONS: PCA and CFA appear useful methods for identifying potential bolt-ons dimensions for an instrument such as the EQ-5D.
OBJECTIVE: Generic preference-based measures such as the EuroQol five-dimensional questionnaire (EQ-5D) are used in economic evaluation, but may not be appropriate for all conditions. When this happens, a possible solution is adding bolt-ons to expand their descriptive systems. Using review-based methods, studies published to date claimed the relevance of bolt-ons in the presence of poor psychometric results. This approach does not identify the specific dimensions missing from the Generic preference-based measure core descriptive system, and is inappropriate for identifying dimensions that might improve the measure generically. This study explores the use of principal-component analysis (PCA) and confirmatory factor analysis (CFA) for bolt-on identification in the EQ-5D. METHODS: Data were drawn from the international Multi-Instrument Comparison study, which is an online survey on health and well-being measures in five countries. Analysis was based on a pool of 92 items from nine instruments. Initial content analysis provided a theoretical framework for PCA results interpretation and CFA model development. PCA was used to investigate the underlining dimensional structure and whether EQ-5D items were represented in the identified constructs. CFA was used to confirm the structure. CFA was cross-validated in random halves of the sample. RESULTS: PCA suggested a nine-component solution, which was confirmed by CFA. This included psychological symptoms, physical functioning, and pain, which were covered by the EQ-5D, and satisfaction, speech/cognition,relationships, hearing, vision, and energy/sleep which were not. These latter factors may represent relevant candidate bolt-ons. CONCLUSIONS: PCA and CFA appear useful methods for identifying potential bolt-ons dimensions for an instrument such as the EQ-5D.
Authors: Aureliano Paolo Finch; Patricia van Velzen; Gerben Ter Riet; Peter J Sterk; Jan M Prins; Judith E Bosmans Journal: Pharmacoeconomics Date: 2019-05 Impact factor: 4.981
Authors: Martine Hoogendoorn; Mark Oppe; Melinde R S Boland; Lucas M A Goossens; Elly A Stolk; Maureen P M H Rutten-van Mölken Journal: Med Decis Making Date: 2019-05-16 Impact factor: 2.583
Authors: Vincent A van Vugt; Judith E Bosmans; Aureliano P Finch; Johannes C van der Wouden; Henriëtte E van der Horst; Otto R Maarsingh Journal: BMJ Open Date: 2020-10-15 Impact factor: 2.692