An empirical comparison of the measurement properties of the EQ-5D-5L, DEMQOL-U and DEMQOL-Proxy-U for older people in residential care

Abstract

PurposeThis study aimed to empirically compare the measurement properties of self-reported and proxy-reported (in cases of severe cognitive impairment) generic (EQ-5D-5L) and condition-specific (DEMQOL-U and DEMQOL-Proxy-U) preference-based HRQoL instruments in residential care, where the population is characterised by older people with high rates of cognitive impairment, dementia and disability.MethodsParticipants were recruited from seventeen residential care facilities across four Australian states. One hundred and forty-three participants self-completed the EQ-5D-5L and the DEMQOL-U while three hundred and eight-seven proxy completed (due to the presence of severe dementia) the EQ-5D-5L and DEMQOL-Proxy-U. The convergent validity of the outcome measures and known group validity relative to a series of clinical outcome measures were assessed.ResultsResults satisfy convergent validity among the outcome measures. EQ-5D-5L and DEMQOL-U utilities were found to be significantly correlated with each other (p < 0.01) as were EQ-5D-5L and DEMQOL-Proxy-U utilities (p < 0.01). Both self-reported and proxy-reported EQ-5D-5L utilities demonstrated strong known group validity in relation to clinically recognised thresholds of cognition and physical functioning, while in contrast neither DEMQOL-U nor DEMQOL-Proxy-U demonstrated this association.ConclusionsThe findings suggest that the EQ-5D-5L, DEMQOL-U and DEMQOL-Proxy-U capture distinct aspects of HRQoL for this population. The measurement and valuation of HRQoL form an essential component of economic evaluation in residential care. However, high levels of cognitive impairment may preclude self-completion for a majority. Further research is needed to determine cognition thresholds beyond which an individual is unable to reliably self-report their own health-related quality of life.

Cost-Effectiveness of Dementia Care Mapping in Care-Home Settings: Evaluation of a Randomised Controlled Trial

“…Previous research has highlighted the challenges in quality-of-life assessment in this group [39]. These challenges relate to the level of missing data, validity of either selfor proxy-reports, and the ability of available measures to capture relevant disease and intervention impacts.…”

“…Equally, it may relate to the sample reporting on this measure. Research suggests individuals with mild cognitive impairment can provide valid self-reports and for those that cannot, proxy reports may be used [39]. However, research is needed to identify the threshold for utility measure selfcompletion and to test methods of combining self-complete and proxy data, which may include adjustment of values or mapping.…”

How Should We Capture Health State Utility in Dementia? Comparisons of DEMQOL-Proxy-U and of Self- and Proxy-Completed EQ-5D-5L

“…Construct validity was examined by comparing utility scores. First, pairs of utility scores generated by different PBMs completed by the same proxy respondent at the same time point were compared (eg, informal carers' EQ-5D-5L-proxy and DEMQOL-Proxy-U responses) using Spearman's rank-order correlation (where correlation ,0.3 was considered weak, 0.3 to ,0.5 moderate, 0.5 to ,0.6 strong, and $0.6 very strong 4 ) and Bland-Altman plots (differences between 2 utility values generated by 2 different PBMs plotted against the mean of the utility values). Second, utility scores generated from the same PBM completed by different respondents at the same time point were compared (eg, informal-carer EQ-5D-5L-proxy vs formal-carer EQ-5D-5L-proxy or resident-completed EQ-5D-5L) using Spearman's rank-order correlation and Bland-Altman plots (first, differences between 2 utility values recorded at the same time point were plotted against the mean, and second, differences between the change in utility values between 2 time points were plotted against the mean at the first time point).…”

“…2 One study showed almost half (48%) of respondents with dementia self-reported having no problems on any EQ-5D dimension (ie, "perfect health"), 3 which seemed unlikely to accurately reflect the respondents' true health state, given the instrument's assessment of such areas as mobility and pain. However, proxy assessors can have different perceptions of another's capabilities and health state, 2,4 perhaps particularly for more unobservable or subjective dimensions (eg, pain or anxiety/ depression vs functional ability), and exhibit additional sources of bias that could differ between individuals. For example, a relative's response might reflect additional emotional burden when compared with formal or employed carers.…”

“…8 The data include a rich combination of resident-completed, proxy-reported, generic, and dementia-specific PBMs in addition to other non-PBM cognitive and HRQOL measures. Although two Australian 4,9 studies have compared the included PBMs, this UKbased study used larger sample sizes, compared more cognitive health and HRQOL measures, and involved modeling temporal within-individual changes, using panel data regression techniques.…”