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Health and Quality of Life Outcomes
Published in: Health and Quality of Life Outcomes 1/2017

Open Access 01-12-2017 | Research

DEMQOL and DEMQOL-Proxy: a Rasch analysis

Authors: A. A. Jolijn Hendriks, Sarah C. Smith, Theopisti Chrysanthaki, Stefan J. Cano, Nick Black

Published in: Health and Quality of Life Outcomes | Issue 1/2017

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Abstract

Background

DEMQOL and DEMQOL-Proxy are widely used patient reported outcome measures (PROMs) of health related quality of life in people with dementia (PWD). Growing interest in routine use of PROMs in health care calls for more robust instruments that are potentially fit for reliable and valid comparisons at the micro-level (patients) and meso-level (clinics, hospitals, care homes).

Methods

We used modern psychometric methods (based on the Rasch model) to re-evaluate DEMQOL (1428 PWDs) and DEMQOL-Proxy (1022 carers) to ensure they are fit for purpose. We evaluated scale to sample targeting, ordering of item thresholds, item fit to the model, and differential item functioning (sex, age, relationship), local independence, unidimensionality and reliability on the full set of items and a smaller item set.

Results

For both DEMQOL and DEMQOL-Proxy the smaller item set performed better than the original item set. We developed revised scores using the items from the smaller set.

Conclusions

We have improved the scoring of DEMQOL and DEMQOL-Proxy using the Rasch measurement model. Future work should focus on the problems identified with content and response options.
Appendix
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Literature
1.
Smith SC, Lamping DL, Banerjee S, Harwood R, Foley B, Smith P, et al. Measurement of health-related quality of life for people with dementia: development of a new instrument (DEMQOL) and an evaluation of current methodology. Health Technol Assess. 2005;9(10):1–93. doi:10.​3310/​hta9100.CrossRef
2.
Smith SC, Murray J, Banerjee S, Foley B, Cook JC, Lamping DL, et al. What constitutes health-related quality of life in dementia? Development of a conceptual framework for people with dementia and their carers. Int J Geriatr Psych. 2005;20:889–95.CrossRef
3.
Smith SC, Lamping DL, Banerjee S, Harwood RH, Foley B, Smith P, et al. Development of a new measure of health-related quality of life for people with dementia: DEMQOL. Psychol Med. 2007;37:737–46.CrossRefPubMed
4.
Department of Health. Equity and excellence: liberating the NHS. London: Department of Health; 2010.
5.
Black N. Patient reported outcome measures could help transform healthcare. BMJ. 2013;346:19–21.CrossRef
6.
Lord FM. Applications of item response theory to practical testing problems. Hillsdale, NJ: Erlbaum; 1980.
7.
Lord FM. Novick MR (with contributions by Birnbaum a). Statistical theories of mental test scores. Reading, MA: Addison-Wesley; 1968.
8.
Andrich D. A rating formulation for ordered response categories. Psychometrika. 1978;43:561–73.CrossRef
9.
Rasch G. Probabilistic models for some intelligence and attainment tests. Copenhagen, Danish Institute for Educational Research. 1960. Expanded edition with foreword and afterword by BD Wright. Chicago: University of Chicago Press; 1980.
10.
Department of Health. Guidance on the routine collection of patient reported outcome measures (PROMs). London: Department of Health; 2008.
11.
Department of Health. The adult social care outcomes framework 2015/16. London: Department of Health; 2014. p. 37.
12.
Department of Health. Prime Minister’s challenge on dementia 2020. Implementation plan. London: Department of Health; 2016. p. 13.
13.
Conaghan PG, Emerton M, Tennant A. Internal construct validity of the Oxford knee scale: evidence from Rasch measurement. Arthritis Rheum. 2007;57:1363–7.CrossRefPubMed
14.
Fitzpatrick R, Norquist JM, Dawson J, Jenkinson C. Rasch scoring of outcomes of total hip replacement. J Clin Epidemiol. 2003;56:68–74.CrossRefPubMed
15.
Fitzpatrick R, Norquist JM, Jenkinson C, Reeves BC, Morris RW, Murray DW, Gregg PJ. A comparison of Rasch with Likert scoring to discriminate between patients’ evaluations of total hip replacement surgery. Qual Life Res. 2004;13:331–8.CrossRefPubMed
16.
Ko Y, Lo N-N, Yeo S-J, Yang K-Y, Yeo W, Chong H-C, Thumboo J. Rasch analysis of the Oxford knee score. Osteoarthr Cartilage. 2009;17:1163–9.CrossRef
17.
Ko Y, Lo N-N, Yeo S-J, Yang K-Y, Yeo W, Chong H-C, Thumboo J. Comparison of the responsiveness of the SF-36, the Oxford knee score, and the knee society clinical rating system in patients undergoing total knee replacement. Qual Life Res. 2013;22:2455–9.CrossRefPubMed
18.
Norquist JM, Fitzpatrick R, Dawson J, Jenkinson C. Comparing alternative Rasch-based methods vs raw scores in measuring change in health. Med Care. 2004;42(Suppl 1):I-25–36.
19.
Mulhern B, Rowen D, Brazier J, Smith S, Romeo R, Tait R et al. Development of DEMQOL-U and DEMQOL-Proxy U: generation of preference-based indices from DEMQOL and DEMQOL-Proxy for use in economic evaluation. Health Technol Assess 2013;17(5):v–xv, 1-140. doi:10.​3310/​hta17050.
20.
Sneeuw KCA, Sprangers MAG, Aaronson NK. The role of health care providers and significant others in evaluating the quality of life of patients with chronic disease. J Clin Epidemiol. 2002;55:1130–43.CrossRefPubMed
21.
Hobart J, Cano S. Improving the evaluation of therapeutic interventions in multiple sclerosis: the role of new psychometric methods. Health Technol Assess. 2009;13(12):1–200. doi:10.​3310/​hta13120.CrossRef
22.
Pallant JF, Tennant A. An introduction to the Rasch measurement model: an example using the hospital anxiety and depression scale (HADS). Brit J Clin Psychol. 2007;46:1–18.CrossRef
23.
Park MH, Smith SC, Neuburger J, Chrysanthaki T, AAJ H, Black N. Sociodemographic characteristics, cognitive function, and health-related quality of life of patients referred to memory assessment services in England. Alzheimer Dis Assoc Disord. 2016; doi:10.​1097/​WAD.​0000000000000166​.
24.
25.
Andrich D, Sheridan B. Rumm 2030. Perth, WA: RUMM Laboratory Pty Ltd; 1997-2016.
26.
Marais I, Andrich D. Formalizing dimension and response violations of local independence in the Unidimensional Rasch model. J Appl Meas. 2008;9(3):200–15.PubMed
27.
Tennant A, Pallant J. Unidimensionality matters! (a tale of two Smiths?). Rasch Meas Trans. 2006;20:1048–51.
28.
Wilson EB. Probable inference, the law of succession, and statistical inference. J Am Stat Assoc. 1927;22:209–12.CrossRef
29.
Brown LD, Cai TT, DasGupta A. Interval estimation for a binomial proportion. Stat Sci. 2001;16:101–33.
30.
31.
Nunnally JC. Psychometric theory. Second ed. New York: McGraw Hill; 1978. p. 28–33.
32.
Lorenzo-Seva U, Ferrando PJ. FACTOR 9.2: a comprehensive program for fitting exploratory and semi-confirmatory factor analysis and IRT models. Appl Psych Meas. 2013;37:497–8.CrossRef
33.
Reise SP, Waller NG, Comrey AL. Factor analysis and scale revision. Psychol Assessment. 2000;12:287–97.CrossRef
34.
Hendriks AAJ, Perugini M, Angleitner A, et al. The five-factor personality inventory: cross-cultural generalizability across 13 countries. Eur J Personality. 2003;17:347–73.CrossRef
35.
Ten Berge JMF, Hofstee WKB. Coefficients alpha and reliabilities of unrotated and rotated components. Psychometrika. 1999;64:83–90.CrossRef
36.
Hofstee WKB, De Raad B, Goldberg LR. Integration of the big five and circumplex approaches to trait structure. J Pers Soc Psychol. 1992;63:146–63.CrossRefPubMed
Metadata
Title
DEMQOL and DEMQOL-Proxy: a Rasch analysis
Authors
A. A. Jolijn Hendriks
Sarah C. Smith
Theopisti Chrysanthaki
Stefan J. Cano
Nick Black
Publication date
01-12-2017
Publisher
BioMed Central
Published in
Health and Quality of Life Outcomes / Issue 1/2017
Electronic ISSN: 1477-7525
DOI
https://doi.org/10.1186/s12955-017-0733-6

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