Skip to main content
SpringerLink
Log in

Psychometric properties of the EQ-5D in a study of people with mild to moderate dementia

  • Published:
Quality of Life Research Aims and scope Submit manuscript

Abstract

Purpose

Due to their cognitive impairment, the health-related quality of life (HRQoL) of patients with dementia is often rated by proxies. This study aims to analyse the psychometric properties of the EQ-5D applied to patients with mild to moderate dementia and their family caregivers.

Methods

Three hundred and ninety patients and their caregivers were asked to assess the patients’ HRQoL using the EQ-5D. The German population-based time trade-off values were used to calculate utility weights. Acceptance, discriminative ability, construct validity, inter-rater agreement and responsiveness were tested. Factors that could have an impact on inter-rater agreement were analysed using a multivariate regression.

Results

Five per cent of patients did not fill out the EQ-5D. The response rate of caregivers and of patients with mild dementia was higher than that of patients with moderate dementia. There were no floor or ceiling effects. The test results of the caregivers concerning construct validity and responsiveness were better than those of the patients. The inter-rater reliability was not satisfactory either on the dimension level or on the utility score level. Caregivers gave the patients’ HRQoL significantly lower ratings than did the patients themselves. Better abilities of the patient to perform activities of daily living and a lower subjective burden of the caregiver were associated with a higher inter-rater agreement.

Conclusions

The study showed that the EQ-5D is especially applicable to patients with mild dementia and their caregivers as proxies. However, there are important differences between patient and proxy ratings, even in cases of mild dementia, at the dimension level as well as utility score level, which should be considered in the interpretation of quality of life scores.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1

Similar content being viewed by others

References

  1. Bickel, H. (2008). Das Wichtigste—Die Epidemiologie der Demenz. Berlin: Deutsche Alzheimer Gesellschaft.

    Google Scholar 

  2. Callahan, C. M., Boustani, M. A., Unverzagt, F. W., Austrom, M. G., Damush, T. M., Perkins, A. J., et al. (2006). Effectiveness of collaborative care for older adults with Alzheimer disease in primary care: A randomized controlled trial. Journal of the American Medical Association, 295(18), 2148–2157.

    Article  CAS  PubMed  Google Scholar 

  3. Spijker, A., Vernooij-Dassen, M., Vasse, E., Adang, E., Wollersheim, H., Grol, R., et al. (2008). Effectiveness of nonpharmacological interventions in delaying the institutionalization of patients with dementia: A meta-analysis. Journal of the American Geriatrics Society, 56(6), 1116–1128.

    Article  PubMed  Google Scholar 

  4. Clegg, A., Bryant, J., Nicholson, T., McIntyre, L., De Broe, S., Gerard, K., et al. (2001). Clinical and cost-effectiveness of donepezil, rivastigmine and galantamine for Alzheimer’s disease: A rapid and systematic review. Health Technology Assessment, 5(1), 1–137.

    Google Scholar 

  5. The EuroHRQoL Group. (1990). EuroHRQoL—a new facility for the measurement of health-related quality of life. The EuroHRQoL Group. Health Policy, 16(3), 199–208.

    Article  Google Scholar 

  6. Aaronson, N. K. (1991). Methodologic issues in assessing the quality of life of cancer patients. Cancer, 67(3), 844–850.

    Article  CAS  PubMed  Google Scholar 

  7. Jonsson, L., Andreasen, N., Kilander, L., Soininen, H., Waldemar, G., Nygaard, H., et al. (2006). Patient- and proxy-reported utility in Alzheimer disease using the EuroHRQoL. Alzheimer Disease and Associated Disorders, 20(1), 49–55.

    Article  PubMed  Google Scholar 

  8. Ankri, J., Beaufils, B., Novella, J. L., Morrone, I., Guillemin, F., Jolly, D., et al. (2003). Use of the EQ-5D among patients suffering from dementia. Journal of Clinical Epidemiology, 56(11), 1055–1063.

    Article  CAS  PubMed  Google Scholar 

  9. Coucill, W., Bryan, S., Bentham, P., Buckley, A., & Laight, A. (2001). EQ-5D in patients with dementia: An investigation of inter-rater agreement. Medical Care, 39(8), 760–771.

    Article  CAS  PubMed  Google Scholar 

  10. Naglie, G., Tomlinson, G., Tansey, C., Irvine, J., Ritvo, P., Black, S. E., et al. (2006). Utility-based quality of life measures in Alzheimer’s disease. Quality of Life Research, 15(4), 631–643.

    Article  PubMed  Google Scholar 

  11. Vogel, A., Mortensen, E. L., Hasselbalch, S. G., Andersen, B. B., & Waldemar, G. (2006). Patient versus informant reported quality of life in the earliest phases of Alzheimer’s disease. International Journal of Geriatric Psychiatry, 21(12), 1132–1138.

    Article  PubMed  Google Scholar 

  12. Long, K., Sudha, S., & Mutran, E. J. (1998). Elder-proxy agreement concerning the functional status and medical history of the older person: The impact of caregiver burden and depressive symptomatology. Journal of the American Geriatrics Society, 46(9), 1103–1111.

    CAS  PubMed  Google Scholar 

  13. Pruchno, R. A., Burant, C. J., & Peters, N. D. (1997). Typologies of caregiving families: Family congruence and individual well-being. Gerontologist, 37(2), 157–167.

    CAS  PubMed  Google Scholar 

  14. Rebollo, P., Alvarez-Ude, F., Valdes, C., & Estebanez, C. (2004). Different evaluations of the health related quality of life in dialysis patients. Journal of Nephrology, 17(6), 833–840.

    PubMed  Google Scholar 

  15. Zanetti, O., Geroldi, C., Frisoni, G. B., Bianchetti, A., & Trabucchi, M. (1999). Contrasting results between caregiver’s report and direct assessment of activities of daily living in patients affected by mild and very mild dementia: The contribution of the caregiver’s personal characteristics. Journal of the American Geriatrics Society, 47(2), 196–202.

    CAS  PubMed  Google Scholar 

  16. Rothman, M. L., Hedrick, S. C., Bulcroft, K. A., Hickam, D. H., & Rubenstein, L. Z. (1991). The validity of proxy-generated scores as measures of patient health status. Medical Care, 29(2), 115–124.

    Article  CAS  PubMed  Google Scholar 

  17. Sands, L. P., Ferreira, P., Stewart, A. L., Brod, M., & Yaffe, K. (2004). What explains differences between dementia patients’ and their caregivers’ ratings of patients’ quality of life? American Journal of Geriatric Psychiatry, 12(3), 272–280.

    PubMed  Google Scholar 

  18. Lauterberg, J., Grossfeld-Schmitz, M., Ruckdaschel, S., Neubauer, S., Mehlig, H., Gaudig, M., et al. (2007). IDA project–concept and implementation of a cluster-randomized trial on dementia management in a general practice setting. Zeitschrift für ärztliche Fortbildung und Qualitätssicherung, 101(1), 21–26.

    Article  PubMed  Google Scholar 

  19. Lubke, N., Meinck, M., & Von Renteln-Kruse, W. (2004). The Barthel index in geriatrics. A context analysis for the Hamburg classification manual. Zeitschrift für Gerontologie und Geriatrie, 37(4), 316–326.

    Article  PubMed  Google Scholar 

  20. Wahle, M., Haller, S., & Spiegel, R. (1996). Validation of the NOSGER (Nurses’ Observation Scale for Geriatric Patients): Reliability and validity of a caregiver rating instrument. International Psychogeriatrics, 8(4), 525–547.

    Article  CAS  PubMed  Google Scholar 

  21. Greiner, W., Claes, C., Busschbach, J. J., & Graf von der Schulenburg, J. M. (2004). Validating the EQ-5D with time trade off for the German population. The European Journal of Health Economics, 6(2), 124–130.

    Article  Google Scholar 

  22. Folstein, M. F., Folstein, S. E., & McHugh, P. R. (1975). “Mini-mental state”: A practical method for grading the cognitive state of patients for the clinician. Journal of Psychiatric Research, 12, 189–198.

    Article  CAS  PubMed  Google Scholar 

  23. Gräßel, E., Chiu, T., & Oliver, R. (2003). Development and validation of the Burden scale for family caregivers (BSFC). Toronto: COTA Comprehensive Rehabilitation and Mental Health Services.

    Google Scholar 

  24. Charlson, M. E., Pompei, P., Ales, K. L., & MacKenzie, C. R. (1987). A new method of classifying prognostic comorbidity in longitudinal studies: Development and validation. Journal of Chronic Diseases, 40(5), 373–383.

    Article  CAS  PubMed  Google Scholar 

  25. Andersen, C. K., Wittrup-Jensen, K. U., Lolk, A., Andersen, K., & Kragh-Sorensen, P. (2004). Ability to perform activities of daily living is the main factor affecting quality of life in patients with dementia. Health and Quality of Life Outcomes, 2(1), 52.

    Article  PubMed  Google Scholar 

  26. Fuh, J. L., & Wang, S. J. (2008). Cost-effectiveness analysis of donepezil for mild to moderate Alzheimer’s disease in Taiwan. Int J Geriatr Psychiatry, 23(1), 73–78.

    Article  PubMed  Google Scholar 

  27. Ikeda, S., Yamada, Y., & Ikegami, N. (2002). Economic evaluation of donepezil treatment for Alzheimer’s disease in Japan. Dementia and Geriatric Cognitive Disorders, 13(1), 33–39.

    Article  CAS  PubMed  Google Scholar 

  28. Teipel, S. J., Ewers, M., Reisig, V., Schweikert, B., Hampel, H., & Happich, M. (2007). Long-term cost-effectiveness of donepezil for the treatment of Alzheimer’s disease. European Archives of Psychiatry and Clinical Neuroscience, 257(6), 330–336.

    Article  PubMed  Google Scholar 

  29. Landis, J. R., & Koch, G. G. (1977). The measurement of observer agreement for categorical data. Biometrics, 33(1), 159–174.

    Article  CAS  PubMed  Google Scholar 

  30. Shrout, P. E., & Fleiss, J. L. (1979). Intraclass correlations: Uses in assessing rater reliability. Psychological Bulletin, 86(2), 420–428.

    Article  CAS  PubMed  Google Scholar 

  31. McGraw, K. O., & Wong, S. P. (1996). Forming inferences about some intraclass correlation coefficients. Psychological Methods, 1(1), 30–46.

    Article  Google Scholar 

  32. Scientific Advisory Committee of the Medical Outcomes Trust. (2002). Assessing health status and quality-of-life instruments: Attributes and review criteria. Quality of Life Research, 11(3), 193–205.

    Article  Google Scholar 

  33. Cohen, J. (1992). A power primer. Psychological Bulletin, 112, 155–159.

    Article  CAS  PubMed  Google Scholar 

  34. Krabbe, P. F., Stouthard, M. E., Essink-Bot, M. L., & Bonsel, G. J. (1999). The effect of adding a cognitive dimension to the EuroHRQoL multiattribute health-status classification system. Journal of Clinical Epidemiology, 52(4), 293–301.

    Article  CAS  PubMed  Google Scholar 

  35. Wolfs, C. A., Dirksen, C. D., Kessels, A., Willems, D. C., Verhey, F. R., & Severens, J. L. (2007). Performance of the EQ-5D and the EQ-5D + C in elderly patients with cognitive impairments. Health and Quality of Life Outcomes, 5, 33.

    Article  PubMed  Google Scholar 

  36. Happich, M., Schweikert, B., & Muhlbacher, A. (2005). Cost-effectiveness of galantamine in a german context. Psychiatrische Praxis, 32(3), 142–150.

    Article  PubMed  Google Scholar 

  37. Tamim, H., McCusker, J., & Dendukuri, N. (2002). Proxy reporting of quality of life using the EQ-5D. Medical Care, 40(12), 1186–1195.

    Article  PubMed  Google Scholar 

  38. Calman, K. C. (1984). Quality of life in cancer patients—an hypothesis. Journal of Medical Ethics, 10(3), 124–127.

    Article  CAS  PubMed  Google Scholar 

  39. Dolan, P., & Kahneman, D. (2008). Interpretations of utility and their implications for the valuation of health. The Economic Journal, 118, 215–234.

    Google Scholar 

  40. Greiner, W., Claes, C., Busschbach, J. J., & Graf von der Schulenburg, J. M. (2005). Validating the EQ-5D with time trade off for the German population. European Journal of Health Economics, 6(2), 124–130.

    Article  CAS  PubMed  Google Scholar 

  41. Hanmer, J., Hays, R. D., & Fryback, D. G. (2007). Mode of administration is important in US national estimates of health-related quality of life. Medical Care, 45(12), 1171–1179.

    Article  PubMed  Google Scholar 

  42. Pickard, A. S., & Knight, S. J. (2005). Proxy evaluation of health-related quality of life: A conceptual framework for understanding multiple proxy perspectives. Medical Care, 43(5), 493–499.

    Article  PubMed  Google Scholar 

  43. Gundy, C. M., & Aaronson, N. K. (2008). The influence of proxy perspective on patient–proxy agreement in the evaluation of health-related quality of life: An empirical study. Medical Care, 46(2), 209–216.

    Article  PubMed  Google Scholar 

Download references

Acknowledgments

The IDA project was initiated and financed by the four partners with equal rights in conception, development and implementation: the Federal Association and the Bavarian organisation of the AOK—the largest statutory health insurance provider in Germany—and the research-based pharmaceutical companies Eisai and Pfizer. The aim of this public-private partnership is to improve the care of patients with dementia and the support of their informal caregivers. I thank the four partners of the IDA project—the Federal Association and the Bavarian organisation of the AOK and the research-based pharmaceutical companies Eisai and Pfizer—as well as Prof. Dr. Elmar Gräßel of the University of Erlangen who made it possible to analyse the data within my doctoral thesis.

Conflict of interest statement

The sponsors have commissioned two academic research institutions with the scientific evaluation of the IDA project by giving unconditional research funds. A contract between the sponsors and academic researchers ensures that the latter have the full scientific responsibility and have the right to publish the results. Members of the sponsoring organisations closely cooperate in the design and conduct of the project, but only the academic researchers have full access to all of the data in this study and take complete responsibility for the integrity of the data and the accuracy of the data analysis.

Author information

Authors and Affiliations

  1. Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Institute of Health Economics and Health Care Management, Ingolstaedter Landstr. 1, 85764, Neuherberg, Germany

    Simone Kunz

Authors
  1. Simone Kunz
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Simone Kunz.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Kunz, S. Psychometric properties of the EQ-5D in a study of people with mild to moderate dementia. Qual Life Res 19, 425–434 (2010). https://doi.org/10.1007/s11136-010-9600-1

Download citation

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11136-010-9600-1

Keywords

Search

Navigation