Validation of the Care-Related Quality of Life Instrument in different study settings: findings from The Older Persons and Informal Caregivers Survey Minimum DataSet (TOPICS-MDS)
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Validity is a contextual aspect of a scale which may differ across sample populations and study protocols. The objective of our study was to validate the Care-Related Quality of Life Instrument (CarerQol) across two different study design features, sampling framework (general population vs. different care settings) and survey mode (interview vs. written questionnaire).
Data were extracted from The Older Persons and Informal Caregivers Minimum DataSet (TOPICS-MDS, www.topics-mds.eu), a pooled public-access data set with information on >3,000 informal caregivers throughout the Netherlands. Meta-correlations and linear mixed models between the CarerQol’s seven dimensions (CarerQol-7D) and caregiver’s level of happiness (CarerQol-VAS) and self-rated burden (SRB) were performed.
The CarerQol-7D dimensions were correlated to the CarerQol-VAS and SRB in the pooled data set and the subgroups. The strength of correlations between CarerQol-7D dimensions and SRB was weaker among caregivers who were interviewed versus those who completed a written questionnaire. The directionality of associations between the CarerQol-VAS, SRB and the CarerQol-7D dimensions in the multivariate model supported the construct validity of the CarerQol in the pooled population. Significant interaction terms were observed in several dimensions of the CarerQol-7D across sampling frame and survey mode, suggesting meaningful differences in reporting levels.
Although good scientific practice emphasises the importance of re-evaluating instrument properties in individual research studies, our findings support the validity and applicability of the CarerQol instrument in a variety of settings. Due to minor differential reporting, pooling CarerQol data collected using mixed administration modes should be interpreted with caution; for TOPICS-MDS, meta-analytic techniques may be warranted.
KeywordsCarerQol-7D Caregivers Quality of life Geriatric health services Visual analogue scale
The authors thank TOPICS-MDS Consortium members for their contribution to this research. The National Care for the Elderly Programme on behalf of the Organisation of Health Research and Development (ZonMw—The Netherlands). TOPICS-MDS Consortium: Project Group W.P.J. den Elzen (Department of Public Health and Primary Care, Leiden University Medical Center, Leiden, Netherlands); A.P.D. Jansen (Department of General Practice and Elderly Care Medicine/EMGO + Institute for Health and Care Research, VU University Medical Center, Amsterdam, Netherlands); G.I.J.M. Kempen (CAPHRI School for Public Health and Primary Care, Department of Health Services Research, Maastricht University, Netherlands), P.F.M. Krabbe (Department of Epidemiology, University of Groningen, University Medical Center Groningen, Netherlands); R.J.F. Melis (Department of Geriatric Medicine, Radboud University Medical Center, Nijmegen, Netherlands); E.P. Moll van Charante (Department of General Medicine, Academic Medical Center, Amsterdam, Netherlands); B. Steunenberg (Julius Center for Health Sciences and Primary Care, UMC Utrecht, Netherlands); E.W. Steyerberg (Department of Public Health, Erasmus MC University Medical Center, Rotterdam, Netherlands); Steering Committee E. Buskens (Department of Epidemiology, University of Groningen, University Medical Center, Groningen, Netherlands), J. Gussekloo (Department of Public Health and Primary Care, Leiden University Medical Center, Leiden, Netherlands); H.E. van der Horst (Department of General Practice and Elderly Care Medicine, EMGO Institute for Health and Care Research, VU University Medical Centre Amsterdam, Netherlands); M.G.M. Olde-Rikkert, (Department of Geriatric Medicine, Radboud University Medical Center, Nijmegen, Netherlands); S.E.J.A. de Rooij (Department of Internal Medicine, Academic Medical Center, Amsterdam, Netherlands); J.M.G.A. Schols (Department of Family Medicine and Department of Health Services Research, CAPHRI School for Public Health and Primary Care, Maastricht University, Maastricht, Netherlands); M.J. Schuurmans (Department of Rehabilitation, Nursing Science and Sports, University Medical Center Utrecht, Netherlands); D. Smilde (Department of Research Policy, Erasmus MC University Medical Centre, Rotterdam, Netherlands); R.G.J. Westendorp (Leyden Academy on Vitality and Ageing, Leiden University Medical Center); Working group D. van den Brink, J.E. Lutomski, L. Qin (Department of Geriatric Medicine, Radboud University Medical Center, Nijmegen, Netherlands).
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