Skip to main content Accessibility help
×
Home

Measuring the quality of life in mild to very severe dementia: Testing the inter-rater and intra-rater reliability of the German version of the QUALIDEM

  • Martin Nikolaus Dichter (a1) (a2), Christian G. G. Schwab (a1) (a2), Gabriele Meyer (a2) (a3), Sabine Bartholomeyczik (a2), Olga Dortmann (a1) (a2) and Margareta Halek (a1) (a2)...

Abstract

Background:

Quality of life (Qol) is an increasingly used outcome measure in dementia research. The QUALIDEM is a dementia-specific and proxy-rated Qol instrument. We aimed to determine the inter-rater and intra-rater reliability in residents with dementia in German nursing homes.

Methods:

The QUALIDEM consists of nine subscales that were applied to a sample of 108 people with mild to severe dementia and six consecutive subscales that were applied to a sample of 53 people with very severe dementia. The proxy raters were 49 registered nurses and nursing assistants. Inter-rater and intra-rater reliability scores were calculated on the subscale and item level.

Results:

None of the QUALIDEM subscales showed strong inter-rater reliability based on the single-measure Intra-Class Correlation Coefficient (ICC) for absolute agreement ≥ 0.70. Based on the average-measure ICC for four raters, eight subscales for people with mild to severe dementia (care relationship, positive affect, negative affect, restless tense behavior, social relations, social isolation, feeling at home and having something to do) and five subscales for very severe dementia (care relationship, negative affect, restless tense behavior, social relations and social isolation) yielded a strong inter-rater agreement (ICC: 0.72–0.86). All of the QUALIDEM subscales, regardless of dementia severity, showed strong intra-rater agreement. The ICC values ranged between 0.70 and 0.79 for people with mild to severe dementia and between 0.75 and 0.87 for people with very severe dementia.

Conclusions:

This study demonstrated insufficient inter-rater reliability and sufficient intra-rater reliability for all subscales of both versions of the German QUALIDEM. The degree of inter-rater reliability can be improved by collaborative Qol rating by more than one nurse. The development of a measurement manual with accurate item definitions and a standardized education program for proxy raters is recommended.

Copyright

Corresponding author

Correspondence should be addressed to: Martin Nikolaus Dichter, German Center for Neurodegenerative Diseases (DZNE), Stockumer Straße 12, 58453 Witten, Germany. Phone: +49 2302926-253; Fax: +49 2302926-239. Email: Martin.Dichter@dzne.de.

References

Hide All
American Psychiatric Association (2000). Diagnostic and Statistical Manual of Mental Disorders. Washington, DC: American Psychiatric Association.
Bonett, D. G. (2002). Sample size requirements for estimating intraclass correlations with desired precision. Statistics in Medicine, 21, 13311335.
Bouman, A. I., Ettema, T. P., Wetzels, R. B., van Beek, A. P., de Lange, J. and Droes, R. M. (2011). Evaluation of QUALIDEM: a dementia-specific quality of life instrument for persons with dementia in residential settings; scalability and reliability of subscales in four Dutch field surveys. International Journal of Geriatric Psychiatry, 26, 711722.
Brod, M., Stewart, A. L., Sands, L. and Walton, P. (1999). Conceptualization and measurement of quality of life in dementia: the dementia quality of life instrument (DQoL). The Gerontologist, 39, 2535.
Carpenter, J. and Bithell, J. (2000). Bootstrap confidence intervals: when, which, what? A practical guide for medical statisticians. Statistics in Medicine, 19, 11411164.
Cohen, J. (1968). Weighted kappa: nominal scale agreement with provision for scaled disagreement or partial credit. Psychological Bulletin, 70, 213220.
Conger, A. J. (1980). Integration and Generalization of Kappas for Multiple Raters. Psychological Bulletin, 88, 322328.
DeVon, H. A. et al. (2007). A psychometric toolbox for testing validity and reliability. Journal of Nursing Scholarship, 39, 155164.
Dichter, M., Bartholomeyczik, S., Nordheim, J., Achterberg, W. and Halek, M. (2011). Validity, reliability, and feasibility of a quality of life questionnaire for people with dementia. Zeitschrift für Gerontologie und Geriatrie, 44, 405410.
Dichter, M.N. et al. (2013a). Scalability and internal consistency of the German version of the dementia-specific quality of life instrument QUALIDEM in nursing homes - a secondary data analysis. Health and Quality of Life Outcomes, 11, 91.
Dichter, M. N., Halek, M., Dortman, O., Meyer, G. and Bartholomeyczik, S. (2013b). Measuring the quality of life of people with dementia in nursing homes in Germany - the Study Protocol for the Qol-Dem Project [Die Erfassung der Lebensqualität von Menschen mit Demenz in stationären Altenpflegeeinrichtungen in Deutschland - Studienprotokoll des Qol-Dem Projektes]. German Medical Science Psychosocial Medicine, 10:Doc07, doi: 10.3205/psm000097.
Efron, B. (1982). The Jackknife, the Bootstrap and other Resamlping Plans. Philadelphia: Society for Industrial and Applied Mathematics.
Efron, B. and Tibshirani, R. (1993). An Introduction to the Bootstrap. London: Chapmann and Hall.
Ettema, T. P., Droes, R. M., de Lange, J., Mellenbergh, G. J. and Ribbe, M. W. (2007a). QUALIDEM: development and evaluation of a dementia specific quality of life instrument - validation. International Journal of Geriatric Psychiatry, 22, 424430.
Ettema, T. P., Droes, R. M., de Lange, J., Mellenbergh, G. J. and Ribbe, M. W. (2007b). QUALIDEM: development and evaluation of a dementia specific quality of life instrument. Scalability, reliability and internal structure. International Journal of Geriatric Psychiatry, 22, 549556.
Ettema, T. P., Droes, R. M., de Lange, J., Ooms, M. E., Mellenbergh, G. J. and Ribbe, M. W. (2005). The concept of quality of life in dementia in the different stages of the disease. International Psychogeriatrics, 17, 353370.
Falk, H., Persson, L. O. and Wijk, H. (2007). A psychometric evaluation of a Swedish version of the Quality of Life in Late-Stage Dementia (QUALID) scale. International Psychogeriatrics, 19, 10401050.
Garre-Olmo, J. et al. (2010). Cross-cultural adaptation and psychometric validation of a Spanish version of the Quality of Life in Late-Stage Dementia Scale. Quality of Life Research, 19, 445453.
Gräske, J., Fischer, T., Kuhlmey, A. and Wolf-Ostermann, K. (2012). Quality of life in dementia care - differences in quality of life measurements performed by residents with dementia and by nursing staff. Aging & Mental Health, 16, 819827.
Halek, M., Dichter, M. N., Quasdorf, T., Riesner, C. and Bartholomeyczik, S. (2013). The effects of dementia care mapping on nursing home residents’ quality of life and staff attitudes: design of the quasi-experimental study Leben-QD II. BMC Geriatrics, 13, 53.
Huang, H. L., Chang, M. Y., Tang, J. S., Chiu, Y. C. and Weng, L. C. (2009). Determinants of the discrepancy in patient- and caregiver-rated quality of life for persons with dementia. Journal of Clinical Nursing, 18, 31073118.
Jonker, C., Gerritsen, D. L., Bosboom, P. R. and Van Der Steen, J. T. (2004). A model for quality of life measures in patients with dementia: Lawton's next step. Dementia and Geriatric Cognitive Disorders, 18, 159164.
Karim, S., Ramanna, G., Petit, T., Doward, L. and Burns, A. (2008). Development of the Dementia Quality of Life questionnaire (D-QOL): UK version. Aging & Mental Health, 12, 144148.
Kottner, J. and Dassen, T. (2008). An interrater reliability study of the Braden scale in two nursing homes. International Journal of Nursing Studies, 45, 15011511.
Landis, J. R. and Koch, G. G. (1977). The measurement of observer agreement for categorical data. Biometrics, 33, 159174.
Lawton, M. P. (1994). Quality of life in Alzheimer disease. Alzheimer Disease and Associated Disorders, 8(Suppl 3), 138150.
Logsdon, R. G., Gibbons, L. E., McCurry, S. M. and Teri, L. (1999). Quality of life in Alzheimer's Disease: Patient and caregiver reports. Journal of Mental Health and Aging, 5, 2132.
Lucas-Carrasco, R., Lamping, D. L., Banerjee, S., Rejas, J., Smith, S. C. and Gomez-Benito, J. (2010). Validation of the Spanish version of the DEMQOL system. International Psychogeriatrics, 22, 589597.
Matsui, T. et al. (2006). Determinants of the quality of life in Alzheimer's disease patients as assessed by the Japanese version of the Quality of Life-Alzheimer's disease scale. Dementia and Geriatric Cognitive Disorders, 21, 182191.
Mayer, H., Nonn, C., Osterbrink, J. and Evers, G. C. (2004). Quality criteria of assessment scales - Cohen's kappa as measure of interrator reliability (1). Pflege, 17, 3646.
Menzi-Kuhn, C. (2006). Quality of life of people with dementia in institutional care [Lebensqualität von Menschen mit Demenz in stationären Langzeitpflegeeinrichtungen]. Master in Nursing Science Masterthesis, Maastricht University.
Moniz-Cook, E. et al. (2008). A European consensus on outcome measures for psychosocial intervention research in dementia care. Aging & Mental Health, 12, 1429.
Novella, J. L. et al. (2001). Agreement between patients’ and proxies’ reports of quality of life in Alzheimer's disease. Quality of Life Research, 10, 443452.
Porzsolt, F. et al. (2004). A new instrument to describe indicators of well-being in old-old patients with severe dementia - the Vienna List. Health and Quality of Life Outcomes, 2, 10.
Rabins, P. V. and Black, B. S. (2007). Measuring quality of life in dementia: purposes, goals, challenges and progress. International Psychogeriatrics, 19, 401407.
Reisberg, B. (2007). Global measures: utility in defining and measuring treatment response in dementia. International Psychogeriatrics, 19, 421456.
Sands, L. P., Ferreira, P., Stewart, A. L., Brod, M. and Yaffe, K. (2004). What explains differences between dementia patients’ and their caregivers’ ratings of patients’ quality of life? American Journal of Geriatric Psychiatry, 12, 272280.
Sloane, P. D. et al. (2007). Dementia care mapping as a research tool. International Journal of Geriatric Psychiatry, 22, 580589.
Smith, S. C. et al. (2005a). 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 Assessment, 9, 1110.
Smith, S. C. et al. (2005b). What constitutes health-related quality of life in dementia? Development of a conceptual framework for people with dementia and their carers. International Journal of Geriatric Psychiatry, 20, 889895.
Social Insurance Code (SGB) Book XI [Sozialgesetzbuch (SGB) Elftes Buch (XI)] (2008). Statutory long-term care insurance (LTCI). [Soziale Pflegeversicherung.]. Bundesgesetzblatt Teil I Nr. 20, 874–906.
Thorgrimsen, L. et al. (2003). Whose quality of life is it anyway? The validity and reliability of the Quality of Life-Alzheimer's Disease (QoL-AD) scale. Alzheimer Disease and Associated Disorders, 17, 201208.
Trigg, R., Jones, R. W. and Skevington, S. M. (2007). Can people with mild to moderate dementia provide reliable answers about their quality of life? Age and Ageing, 36, 663669.
Weiner, M. F., Martin-Cook, K., Svetlik, D. A., Saine, K., Foster, B. and Fontaine, C. S. (2000). The quality of life in late-stage dementia (QUALID) scale. Journal of the American Medical Directors Association, 1, 114116.
WHO (1995). The World Health Organization Quality of Life assessment (WHOQOL): position paper from the World Health Organization. Social Science & Medicine, 41, 14031409.
Wolak, A. et al. (2009). Transcultural adaptation and psychometric validation of a French-language version of the QoL-AD. Aging & Mental Health, 13, 593600.

Keywords

Metrics

Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed