Use of the EQ-5D among patients suffering from dementia

doi:10.1016/S0895-4356(03)00175-6

Journal of Clinical Epidemiology

Volume 56, Issue 11, November 2003, Pages 1055-1063

https://doi.org/10.1016/S0895-4356(03)00175-6 Get rights and content

Abstract

Background and objective

This study was designed to determine the acceptability, feasibility, reliability, and validity of the French version of EQ-5D measuring HRQol in subjects with dementia.

Methods

EQ-5D was administered to 142 subjects. The feasibility and acceptability were determined by the refusal rate, the type of administration, and the percentage and distribution of missing data. Test-retest reliability was studied by kappa coefficients and validity by agreement between subjects' and proxies' assessments.

Results

The response rate was satisfactory. The instrument discriminated well among the subjects. Test-retest reliability was average. The validity was poor if we consider the agreement between patients' and caregivers' reports, but other criteria of validity produced better results. Subjects' responses on each dimension were related with their global judgment of health in the expected direction. Significant relations were found between the Katz index of ADL and self-rated difficulties only for expected dimensions. Relations with age and with gender were in line with expectations.

Conclusion

Results led to consider that patients' responses are not entirely devoid of judgment. It seems that dementia patients are capable of expressing their health-related quality of life through a brief instrument as the EQ-5D.

Introduction

Health-related quality of life (HRQOL) has become a high priority in health and social services for the elderly, a population in which cognitive function is sometimes impaired because of dementia. The prevalence of dementia in people over 65 is 5%, but the rate increases sixfold in people over 90 [1]. Factors associated with dementia can pose methodologic problems in evaluating quality of life in this population, raising questions about the validity of such evaluations. Impaired memory, judgment, and language, which are typical of dementia, may make it impossible to administer a quality-of-life questionnaire. Interpreting a self-evaluation of health-related quality of life in patients denying their disease state may also be problematic. Given the frequency of psychologic and behavioral problems that, themselves, undermine quality of life, one might question the pertinence of such evaluations. But if a patient is able to complete a self-assessment of HRQOL, may this fact be considered as a valid indicator of her (his) HRQOL in itself?

The effects of intellectual deterioration on subjects' comprehension, expression of expectations and wishes, and language, have led certain investigators to conclude that these patients are not by themselves able to evaluate their quality of life. Therefore, an indirect approach is often taken, relying on family or institutional proxies for evaluation [2], [3], but some researchers question the validity of such assessments [4], [5], [6], [7], [8]. On the other hand, Kiyak et al. [9], in a longitudinal study, showed that, contrary to a widely accepted belief, patients with Alzheimer's disease are conscious of the decline in their functional and cognitive abilities.

So, it makes sense to ask whether a brief HRQOL instrument may be used in such a population.

There are several health-related quality-of-life scales in French that have been validated on elderly people, some suffering from cognitive impairment [10], [11], [12]. One of these, the EQ-5D [13], has the advantage of being a generic instrument, and therefore, allows for comparisons between people in different age groups and with different pathologies. Another advantage is that it contains few items, making it suitable for administration to subjects with dementia.

Section snippets

Aim of the study

This study was designed to ascertain the acceptability, feasibility, reliability, and validity of the EQ-5D for a French population of subjects suffering from dementia.

Patient sample

Subjects (male and female) were recruited by 16 French geriatric hospital centers belonging to the French “Réseau Qualité de vie et Démence” to ensure a broad range of disease severity and settings. The patient population was hospitalized in geriatric care units (for various conditions), institutionalized, or outpatients. To be included in the study, subjects had to be at least 60 years old and present a dementia according to the DSMIII-R diagnostic criteria. Patients who were blind, seriously

Determination of an overall score

The EQ-5D was designed to provide profiles on health status. The possible responses to each item are ordinal categories, and therefore, no allowance was made for an overall score based on a combination of the responses. It appeared, however, that the instrument might legitimately be used to establish an overall score. If the ordinal responses are converted into numerical ratings, a score can be obtained for each item, and scores can be added.

The refusal rate was taken as a measurement of

Results

A total of 142 patients were included in the study (Table 1). There were 29 men (20.4%) and 113 women (79.6%). Their average age was 82.9 years, with a range of 60 to 99 years, and one in five subjects lived at home. On average, the women were older, widows, and lived more often in an institution. They had less schooling than men in the sample. In most cases, the dementia was associated with Alzheimer's disease (70.4%), followed by vascular dementia (12.7%). As measured by the CDR, slightly

Acceptability

One hundred thirty-seven of the 142 patients accepted to complete the questionnaire.

Feasibility

Although 14 subjects were able to complete the questionnaire on their own, the vast majority (n = 123) responded with the help of a trained interviewer. Subjects who self-administered the questionnaire had a significantly higher MMSE score than those who did not (18 vs. 12.4; t = 3.72; P<.0001). Average time to complete the questionnaire was 15.3 min, but the variability (SD = 13.9) was high, with some subjects taking

Test-retest reliability

Test-retest reliability was determined by having the questionnaire administered a second time to 47 randomly selected patients after a 3-day interval. Kappa coefficients obtained (Table 3) reflected a moderate concordance, and even a weak concordance for pain/discomfort.

The significant intraclass correlation coefficient found for the VAS showed average correlation and concordance [ICC(2.1) = 0.44, P = .004]. The mean difference in evaluation between the two administrations was moderate (5.72 points

Discussion

In this study, the EQ-5D was administered to a sample of patients with dementia as defined by internationally accepted criteria. Even though EQ-5D is intended to be self-administrated, the questionnaire was almost always administered in our study by an interviewer. Given the impairments in this population and the methodology used in previous studies, allowance was made for this possibility in the study design. Some studies have found no differences between the results from self-administered and

Conclusion

Overall, this study seems to show that an evaluation of quality of life with the EQ-5D questionnaire is possible in patients with dementia. The severity of the pathology has little effect on the instrument's reliability and validity, but it does affect its acceptability.

The questionnaire was well received and the response rate was good, except for the VAS, which seems to present problems. Even if the test-retest reproducibility and the agreement between patient responses and proxy responses

Acknowledgements

This study was made possible by funding from: DG V of the European Commission, Contract No. SOC972016 18O5F03(97CVVF34180); INSERM, Contract No. 4R0 02C; The Conseil Régional de Champagne Ardenne; The Recherche et Partage foundation; and The Régate association.

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View full text

Use of the EQ-5D among patients suffering from dementia

Abstract

Background and objective

Methods

Results

Conclusion

Introduction

Section snippets

Aim of the study

Patient sample

Determination of an overall score

Results

Acceptability

Feasibility

Test-retest reliability

Discussion

Conclusion

Acknowledgements

J Psychiatr Res

J Clin Epidemiol

J Clin Epidemiol

J Clin Epidemiol

J Clin Epidemiol

J Clin Epidemiol

Soc Sci Med

Soc Sci Med

Soc Sci Med

J Clin Epidemiol

Soc Sci Med

Prevalence of dementia and major subtypes in Europe. A collaborative study of population based cohorts. Neurologic Diseases in the Elderly Research Group

Neurology

Quality of life in patients with Alzheimer's disease as reported by patient proxies

J Am Geriatr Soc

Use of proxies to measure health and functional outcomes in effectiveness research in persons with Alzheimer's disease and related disorders

Alzheimer Dis Assoc Disord

Conceptualization and measurement of quality of life in dementia: The Dementia Quality of Life Instrument (DQoL)

Gerontologist

Are proxy assessments of health status after stroke with the EQ-5D questionnaire feasible, accurate and unbiased?

Stroke

Agreement between self reports and proxy reports of quality of life in epilepsy patients

Qual Life Res

Proxy reliability: health-related quality of life (HRQoL) measures for people with disability

Qual Life Res

Comparison of older adult subject and proxy responses on the SF-36 health-related quality of life instrument

Aging Ment Health

Physical and functional health assessment in normal aging and in Alzheimer's disease: self-report vs family reports

Gerontologist

Using the SF-36 and EQ-5D on an elderly population

Qual Life Res

Use of the EuroQol among elderly acute care patients

Qual Life Res

Reliability and validity of the EuroQol in patients with osteoarthritis of the knee

Rheumatol

A new clinical scale for the staging of dementia

Br J Psychiatry

Progress in development of index of, ADL

Gerontologist

Testing the validity of the Euroqol and comparing it with the SF-36 Health Survey Questionnaire

Qual Life Res