Quality of Life of Nursing Home Residents with Dementia: Validation of the German Version of the ICECAP-O
Brouwer WBF (2014) Quality of Life of Nursing Home Residents with Dementia: Validation of the German Version of the
ICECAP-O. PLoS ONE 9(3): e92016. doi:10.1371/journal.pone.0092016
Quality of Life of Nursing Home Residents with Dementia: Validation of the German Version of the ICECAP-O
Peter Makai 0
Franziska Beckebans 0
Job van Exel 0
Werner B. F. Brouwer 0
Terence J. Quinn, University of Glasgow, United Kingdom
0 1 Department of Geriatrics, Radboud University Medical Centre , Nijmegen , The Netherlands, 2 Siemens Health Insurance Fund, Munchen, Germany , 3 Institute of Health Policy and Management, Erasmus University Rotterdam , Rotterdam , The Netherlands
Objectives: To validate the ICECAP-O capability wellbeing measure's German translation in older people with dementia living in a nursing home, and to investigate the influence of proxy characteristics on responses. Method: Cross-sectional study. For 95 residents living in a German nursing home, questionnaires were completed by nursing professionals serving as proxy respondents. We investigated the convergent validity of the ICECAP-O with other Quality of Life (Qol) measures, the EQ-5D extended with a cognitive dimension (EQ-5D+C), the Alzheimer's Disease Related Quality of Life (ADRQL) measures, and the Barthel-index measure of Activities of Daily Living (ADL). Discriminant validity was investigated using bivariate and multivariate stepwise regression analysis, comparing ICECAP-O scores between subgroups varying in dementia severity, care dependency, ADL status and demographic characteristics. Results: Convergent validity between the ICECAP-O, EQ-5D+C, ADRQL and Barthel-Index scores was moderate to good (with correlations of 0.72, 0.69 and 0.53 respectively), but differed considerably between dimensions of the instruments. Discriminant validity was confirmed by finding differences in ICECAP-O scores between subgroups based on ADL scores (0.58 below 65 points on the Barthel-index and 0.80 above 65 points) and other characteristics. The ICECAP-O scores based on available tariffs were related to proxy characteristics gender (0.52 males versus 0.65 females) and work experience (0.61 below 2 years of experience versus 0.68 above 2 years). Discussion: The results of this study suggest that the ICECAP-O is a promising generic measure for general Qol and capability of people with dementia living in a nursing home. Validity tests generally yielded favorable results. Work experience and gender appeared to influence proxy response, which raises questions regarding appropriate proxies, especially since the ICECAP-O may be completed by proxies relatively often. Further research is necessary to validate the German version of the ICECAP-O, with specific attention to proxy completion for people with dementia.
. These authors contributed equally to this work.
Growing life expectancy leads to higher numbers of people with
dementia due to increasing risk of incidence of dementia with age
. Currently, 57% of older people above 60 years suffer from
dementia and this figure is expected to have doubled by 2030 .
Most people with dementia initially receive informal care at home,
but with the progression of the disease, the amount of professional
care typically increases. Frequently, in advanced stages of the
disease, a sufficient amount and quality of professional care can
only be provided in an institutional long-term care setting, making
admissions inevitable for a growing number of people with
dementia . Faced with increasing demand, the long-term care
sector in many countries may experience strong budgetary
pressures, raising questions of optimal resource allocation and
affordability of care.
Economic evaluation has traditionally assisted allocation
decisions by integrally measuring health status and mortality using the
QALY (Quality Adjusted Life Year) concept. In QALY
calculations, values (often referred to as utility scores) are assigned to
different health states, which allows the quantification of health
gains comprising both length and quality of life gains from
interventions . These health states are commonly measured
using Health-Related Quality of Life (HrQoL) instruments, which
are used for computing the quality adjusted component of QALYs.
This makes HrQol instruments an essential outcome measure for
economic evaluation. Measurement of HrQoL is important for a
chronic disease such as dementia, which impairs the quality of life
of affected patients in addition to their length of life . HrQoL is
most commonly measured with the EQ-5D instrument .
Economic evaluation is increasingly used in the curative sector
as a decision support tool for resource allocation, but may aid the
allocation of resources in long-term care as well   .
However, quality of life of individuals does not only depend on
generically assessed HrQoL, as for instance measured by the
EQ5D, but also depends on other, non-health dimensions . This is
important in the context of economic evaluations when
interventions do not (only) affect HrQoL but also these other factors of
overall quality of life. For example, people with dementia living in
nursing homes may have less contact with their family members,
which may reduce their feelings of attachment and, consequently,
general quality of life or well-being. Additionally, people suffering
from advanced stages of dementia forget where they are, loose
their sense of time and may no longer recognize their own family
members  , which may lead to a decreased sense of control,
and may inhibit their feeling of being valued. Therefore, to ensure
a sense of accomplishment and independence for people with
dementia, other activities matching their abilities and remaining
resources are offered in nursing homes, for example through
providing engaging activities  . Such activities do not
necessarily lead to an improvement in health, but will improve
nursing home residents QoL more broadly by increasing their
enjoyment of life, feeling of control and may contribute to a feeling
of being valued. HrQoL instruments like the EQ-5D may not
adequately reflect these elements of broader quality of life and
therefore not be sufficient for a full economic evaluation of
longterm care facilities .
Disease specific quality of life measures, such as the Dementia
Quality of Life instrument (D-QOL) , the QuAlity of LIfe
Measure for people with DEMentia (QALIDEM) , the
Cornell-Brown Scale , the Qol-AD  and the Alzheimer
Disease Related Quality of Life (ADRQL)  aim to capture
such dementia-specific aspects of quality of life, with dimensions
such as awareness of self and response to surroundings, feeling and
belonging, and positive effect and negative affect . Some
dementia-specific outcome measures, such as the ADRQL have
subscales and summary scores as well, translating a
multidimensional HrQoL construct into a summary measure facilitating
treatment comparisons . However, by focusing on the effects
of one particular disease, such measures may not capture the effect
of other morbidities on HrQoL. This is of particular relevance to
the nursing home population, where older people typically suffer
from a range of co-morbidities , making it difficult to perform
a complete assessment of the impact of specific interventions using
disease-specific HrQoL instruments alone.
In order to be able to perform a complete economic evaluation
the full benefit of the evaluated intervention or service should be
measured. For this purpose, broader HrQoL measures, often
named wellbeing measures, should be used to capture more facets
of peoples lives than health status alone. A recently developed
wellbeing instrument, the ICECAP-O (ICEpop CAPability
measure for Older people), aims to incorporate such aspects
beyond health  . These broader wellbeing aspects are
captured through the notion of capabilities, based on Amartya
Sens capability approach . Capabilities refer to the potential
to achieve certain states and perform certain actions. Having the
capability to live life the way one desires is obviously important,
also to older people, and reduction of this capability limits their
wellbeing  . The ICECAP-O was originally developed to
provide a set of general capability values which thus differ from
QALY values- for use in economic evaluations for people above 65
in the UK. Previous validation studies confirmed that the
ICECAP-O evaluates a spectrum of outcomes beyond HrQoL
 . So far, the ICECAP-O has been used in the general
population in the UK  and Australia , in a
psychogeriatric nursing home setting in the Netherlands , and among
older adults with mobility impairments in Canada .
Measuring HrQoL and wellbeing in elderly suffering from
dementia raises special challenges. At the stage of intermediate
and advanced dementia the disease affects cognitive abilities and
people lack the capacity of self-completing questionnaires (even in
an interview setting) due to loss of memory, attention and language
. For all instruments in this study, we therefore used the
proxyreport as suggested in the literature among people with moderate
to severe levels of cognitive disorders      .
The choice of proxy may influence response, as professional and
family proxies respond differently to HrQoL and wellbeing
questionnaires in general   and specifically for the
ICECAP-O . In case of psycho-geriatric residents, nursing
professionals have been recommended as proxy to complete the
ICECAP-O . However, the influence of respondent
characteristics beyond being a family member or a professional caregiver
on the ICECAP-O remains unknown.
Measuring wellbeing is important in German long-term care as
well. Around 1.3 million Germans suffer from dementia and this
figure is expected to reach almost 2 million by 2040 . In
addition, institutionalization of people with dementia is quite
common in the German context, and 40% of elderly with
dementia are institutionalized  . About 60% of nursing
home residents in Germany suffer from dementia and require
appropriate care . Within the German long-term care system,
three levels of care dependency are distinguished: low, medium
and high care dependency, translating into a care requirement of
daily assistance, 3 times assistance per day and 24 hours of care
per day . While levels of required care do not specify the
location of care, mainly the second and third care dependency
categories are represented in the institutional setting . In
addition, institutional care is seen mainly as a last resort when
adequate care provision is no longer available or feasible at home
due to social and familial circumstances or the severity of illness
The aim of this study was to investigate the convergent validity
and the discriminant validity - i.e., the ability to discriminate
between subgroups, sometimes also termed clinical validity - of the
ICECAP-O in a population of elderly with dementia living in a
nursing home. Furthermore, we will explore whether proxy
characteristics influence response.
Design, Setting, Study Population and Data Collection
We performed a cross-sectional study in two separate sites of a
specialized nursing facility for dementia patients between May and
August 2011 in North Rhine-Westphalia, Germany. The sample
size consisted of 95 residents diagnosed with dementia, who were
older than 55 and had been living in the nursing home for longer
than two months. Nursing professionals (nurses, care assistants and
nursing assistants) were selected as proxy respondents if they were
primary caregivers of the dementia patient. Primary caregivers
were defined as the persons who had the most experience with
taking care of particular residents and were involved in their care
at least four times a week. Nursing professionals were asked to
complete the questionnaire in a manner as the client would have, if
he/she would have been able to answer the questions. In total, 11
nursing professionals completed between 4 and 20 written
questionnaires each. The Ethical Committee of the German
Society for Nursing stated their formal approval was not required
to conduct the study due to its non-invasive nature. Written
informed consent was obtained from legal guardians for all 95
residents. To ensure privacy, the researchers did not see the name
list of the residents at any time in the study.
Dementia status. Dementia status was measured using the
general practitioners diagnosis: type according to the ICD-10
(F00.-, F01.- or F02.-)  and severity according to the German
guideline for dementia . This classification is based on the
Mini Mental Score Examination (MMSE), with mild dementia
corresponding to MMSE scores between 20 and 26, moderate
dementia corresponding to MMSE scores from 10 to 19 and
severe dementia corresponding to MMSE scores below 10 .
Furthermore, care dependency (1 = low/2 = medium/3 = high
care dependency) was measured using the care-level classification
of the German National Association of Statutory Health Insurance
Funds . According to this classification, people in care level 1
need help once a day in some ADL activities, people in care level 2
need help three times a day, while people in care level 3 need
continuous nursing care .
Wellbeing. The ICECAP-O measures capability wellbeing
using five domains or attributes (attachment, security, role,
enjoyment and control) and distinguishing four levels within each
domain (levels generally range from all, lot, little, not any; exact
wording of levels varies per dimension). The ICECAP-O thus
distinguishes a total of 1,024 wellbeing states  . The
attributes were identified and formulated through extensive
qualitative empirical research . In order to obtain tariffs for
the well-being states described with the ICECAP-O, the attributes
were valued using best-worst scaling, a special type of discrete
choice analysis . The ICECAP-O tariffs have values between 0
(no capabilities) and 1 (full capabilities). In this study British tariffs
were applied as German tariffs are lacking. For this first use of the
ICECAP-O in Germany, the questionnaire was forward-backward
translated from English into German by two independent
Health-related quality of life. We used the revised 40-Item
version of the Alzheimer Disease Related Quality of Life
(ADRQL) instrument, which allows for the assessment of QoL
for people with mild, intermediate or late-stage dementia using
proxy response     . The dementia-specific,
multi-dimensional ADRQL instrument can be completed by
family members or patients professional caregivers   
. The ADRQL measures the dimensions Social Interaction,
Awareness of Self, Enjoyment of Activities, Feelings and Mood,
and Response to Surrounding . The various dimensions range
from 4 to 12 items on a dichotomous scale and each item is
weighted in a range between 9.15 and 13.75, based on a judgment
of importance by caregivers . For each dimension a separate
subscale can be calculated and summed up in one total score
ranging from 0 (lowest quality of life) to 100 (highest quality of life)
. The instrument exhibits good psychometric properties
having adequate validity, good internal-consistency reliability,
very low missing data and good sensitivity to change  .
The authorized German edition of the ADRQL was used .
The EQ-5D as developed by the EuroQol group is a common
instrument to measure generic HrQol . The EQ-5D measures
five dimensions (mobility, self-care, usual activities,
pain/discomfort, anxiety/depression) on three levels (no problems, some
problems, extreme problems)  , describing 243 health
states. The EQ-5D health states can be converted to a utility score
by applying the German EQ-5D index, based on TTO values 
. The EQ-5D utility scores range from 1 (perfect health)
through 0 (dead) and has negative values accounting for health
states worse than dead. For use in people with dementia, the
EQ5D was extended with a cognitive dimension, for which utility
scores are unavailable  . In this study the official German
proxy version 2 of the EQ-5D was used  and a German
translation of the question pertaining to the cognitive dimension
Activities of daily living. The Barthel-Index is a
wellestablished instrument that measures residents ability to perform
activities of daily living (ADL) by proxy- or self-report. Decrease in
ADL is one of the visible manifestations of dementia, and the
subsequent loss of independence . The ADL-score is mainly
used in geriatric fields and is a strong predictor of QoL scores
across several outcome measurements, including the ADRQL 
. The Barthel-Index includes items such as personal care and
moving from wheelchair to bed and back, measured on two to four
levels depending on the item. The available scores per question are
0 and 5 for two-level items, 0, 5, and 10 for three-level items and 0,
5, 10 and 15 for four level items, ranging from inability to
independence. The total score thus ranges between 0 (completely
dependent) and 100 (completely independent)   with a
cutoff score of 65 indicating need for ADL assistance . In this
study the validated German version was used .
Patient and proxy characteristics. Additionally, we
collected data on patients age, sex, marital status, length of stay in
the nursing home, and frequency of visits by family members.
Finally, the questionnaire contained questions on age, role, work
experience and length of time the nurse selected as proxy
respondent knew the resident, since previous studies have shown
that proxy characteristics may influence responses  .
To establish convergent validity we expected moderate to strong
and positive correlations between the ICECAP-O, the EQ-5D and
ADRQL scores because all of these instruments measure (partial)
operationalizations of QoL (H1). Furthermore, we expected a
moderate and positive correlation between the ICECAP-O
dimension and tariff scores and the Barthel-index (H2).
For discriminant validity, we expected to find differences in
ICECAP-O tariff scores between residents suffering from severe
and mild/moderate dementia (based on the MMSE), between
ADL dependent (Barthel score ,65) and ADL independent
(Barthel score $65) residents, between low, medium and high care
dependency groups, and between older (75+ years) and younger
(,75 years) residents (H3). A higher score on the ICECAP-O was
expected for the better-off groups.
We expected that the proxy characteristics function (leading/
non-leading), work experience (more or less than 2 years) and time
knowing the resident (more or less than a year) would influence
response on the ICECAP-O instrument (H4).
Descriptive statistics of resident and proxy characteristics were
calculated. Correlations between the outcomes of the ICECAP-O
and dimensions of the ADRQL, EQ-5D and the ADL were used
to estimate convergent validity. Correlations above 0.5 were
considered as strong, between 0.3 and 0.5 as moderate, and below
0.3 as weak . Discriminant validity was analyzed using t-test
and one-way-ANOVA to explore differences in means of the
ICECAP-O between different demographic and dementia-related
groups. Discriminant validity was also examined using two
stepwise multivariate regressions, the first model controlling for
patient variables (dementia severity, age, gender, time living in the
nursing home, marital status, dementia type, ADL, frequency of
visit, care level), and the second model for proxy characteristics as
well (proxy gender, years of experience, function, time knowing
the resident). For the stepwise analyses we used a cutoff of 0.1 for
entering variables, using the forwards stepwise algorithm of
There was no missing data, so there was no need to correct for
this in the study. For all analyses the level of significance was p,
0.05. Data was analyzed using STATA 11.
Descriptive statistics of the 95 residents and the proxies are
presented in Table 1. Average age of the residents was 77 years,
with 54% being female and 55% of residents living in the nursing
home for more than 2 years. 60% had Alzheimers dementia, and
dementia severity could be categorized as severe in 60% of the
cases. The majority of the residents (56%) had visitors less than
once a week. As for the characteristics of the proxy respondents,
the majority of the proxy respondents were female, and, on
average, they had worked at the nursing home for 3.5 years.
Figure 1 illustrates the response to the ICECAP-O questions.
On most dimensions, the majority of the residents had at least
some deficits in terms of capabilities.
Table 2 describes the dimension and tariff scores of the
measurement instruments used. The overall average scores for the
instruments were as follows: average ICECAP-O score (based on
the tariffs) was 0.63, EQ-5D score was 0.53, and the ADRQL
score (based on tariffs) was 70.36.
Table 3 shows that the ICECAP-O scores were strongly
correlated with EQ-5D scores, ADRQL scores and Barthel scores.
Correlations between the ICECAP-O tariff scores and the
different dimensions of the EQ-5D+C were generally strong and
significant, except for the EQ5D+C dimensions pain and
anxiety. Correlations between the ICECAP-O and the ADRQL
proved to be similarly strong and significant, with the exception of
the ADRQL dimensions Feeling and Mood (FM) and
Response to the Surroundings (RS). The individual
ICECAPO dimensions Role and Control were strongly and significantly
correlated with the EQ-5D+C dimensions mobility, self-care, usual
activities and cognition. Role was also significantly and strongly
correlated with AS (ADRQL). The Barthel index was significantly
correlated with all ICECAP-O dimensions except for security,
with correlations between the Barthel index and the role and
control dimensions being particularly strong.
Table 4 shows the means of the ICECAP-O tariff scores in
various subgroups defined by resident and proxy characteristics.
Type of dementia (Alzheimers)
Length of stay in nursing home
Frequency of visits by family members
Working time (months)
Time knowing the resident (months)
once a week or more
less than once a week
Level 2 (Medium)
The results of the t-tests showed significant differences in ICECAP
scores between patients with different dementia severity (mild,
moderate, severe), ADL scores (,65, $65) and ages (i.e., above or
below 75). ANOVA results showed that the ICECAP-O tariff
- scores based on tariff
- dimension scores
- dimension scores (+C)
- dimension scores
scores differentiated between residents classified into different care
dependency levels. As expected, lower scores were observed for the
more severe groups, and higher for the less severe groups.
Social Interaction (SI)
Awareness of Self (AS)
Feelings and Mood (FM)
Enjoyment of Activities (EA)
Response to Surroundings (RS)
I.C ch tyep irsn tsu
le4b ilraeb itsend e rend itaenm iennu ilrttaaS its llrveee
a a e g e e im a is a
T V R A G D T M V C
it e g
r c n
e n i
sve ire ow
e n n 7
itaeenm LD rcyxoh reend rxkeop tskhno itconnu -rsaeuq a:teoU .:i0113o
D A P G W M F R N d
Additionally, the ICECAP-O tariff scores varied with two proxy
characteristics: gender and work experience.
Table 4 also shows the discriminant validity of the ICECAP-O
tariff scores in a multivariate analysis. A relatively weak, but
significant association was observed between the ICECAP-O tariff
scores and ADL scores in both the model with only patient
characteristics (analysis not shown) and in the model also including
proxy characteristics. ADL coefficients, standard deviations and
pvalues were identical in both models. From the proxy
characteristics, nursing professionals gender and work experience were
associated with the ICECAP-O tariff scores.
In this study the ICECAP-O was used and validated for the first
time in Germany, in a specialized nursing home for dementia
patients. Our results indicate that the ICECAP-O has good
convergent validity. Hypotheses were supported by the significant
and strong correlations of the ICECAP-O tariff scores with
HrQoL scores (both EQ-5D and ADRQL scores) (H1) and with
ADL scores (H2). Moreover, as hypothesized (H3), the
ICECAPO significantly discriminated between subgroups based on
dementia severity (mild, moderate and severe), ADL status (,65;
$65), care level (low/middle/high) and age (residents younger and
older than 75 years), thus supporting discriminant validity. In the
stepwise multivariate model, the ICECAP-O discriminated
between nursing home residents with different ADL status. The
exploration of the relationship between the proxy responses on the
ICECAP-O showed a significant influence of proxy characteristics
on the ICECAP-O tariff scores (confirming H4).
Some limitations of this study deserve mentioning. First,
residents all lived in two sites of the same nursing home facility
and were not randomly selected. Therefore, they may have
characteristics that differ from the typical population with
dementia in German nursing homes. Hence, the results presented
here are neither necessarily representative nor generalizable.
However, the focus of the study was the validation of the
properties of a wellbeing instrument in relation to various HrQoL
instruments. For that purpose, the current sample seems adequate.
Obviously, confirmation of these findings in other samples and
settings remains important.
Second, at the time of this study, the ADRQL was the only
dementia-specific instrument applicable to all stages of dementia
available in German. Hence, this instrument was selected. In the
meantime, however, a number of other measures have been
validated in Germany, such as the Qol-Ad , the D-Qol ,
and the QALIDEM . Further research to establish the
convergent validity of the ICECAP-O with these instruments
would be valuable.
Third, the sample size was relatively small. Hence, also in light
of the promising results reported here, further research in larger
samples is encouraged. Specific attention should also be paid in
future research to the influence of proxy characteristics.
Fourth, nursing proxies completed varying numbers of
questionnaires, which may have influenced our results. However, due
to sample size considerations this could not be investigated in
A fifth limitation is that only nursing proxies were used. Family
members and spouses, who may assess residents QoL on the
ICECAP-O differently than nursing professionals do , were
not approached. It may be argued, that family members have a
greater understanding of the individual and how they would
perceive their own wellbeing since they will normally have known
the patient for a much longer period of time as well as more
profoundly. At the same time, family members are likely to
compare the current state of the patients to their previous state(s),
i.e. in relatively good health. This may induce them to focus more
on the loss of health and wellbeing compared to before than on the
current state for instance in comparison to other patients. Nursing
professionals care for the residents on a day to day basis, at present
have more contact with the residents than family members
(frequently observing physical and mental conditions of patients,
not only during visiting hours), and thus may be able to access the
current QoL of elderly more accurately, also in comparison to
other patients with dementia. Therefore, as suggested previously
, in this care setting the nurse as proxy respondent seems to be
the logical choice. Still, further research investigating the
differences between family and nursing proxies is encouraged.
Finally, since German tariffs for the ICECAP-O were not
available, British tariffs were used in this study. Although
preference weights for capability dimensions may vary between
countries, it is questionable whether using German tariffs (if
available) would have led to different results regarding the validity
of the ICECAP-O instrument. At the time of this study no
ADRQL tariffs were available for Germany either, therefore we
used the official American tariffs . In order to investigate
possible cultural effects on the valuation of the ADRQL, we
performed a sensitivity analysis (results not shown) using weights
from the German-speaking region of Switzerland, obtained in a
pilot study . Using these ADRQL weights in the sensitivity
analysis did not yield different results.
Convergent Validity and Discriminant Validity
The average ICECAP-O tariff score found in this study within a
nursing home setting (0.63) was comparable to the score reported
in a Dutch study performed in nursing homes (0.63) , and was
substantially lower than the score for community-living elderly,
where the average scores ranged between 0.810.84 [26,27,63
68]. These findings support the reliability of our results.
The strong correlation between the ICECAP-O and EQ-5D
scores shows that generic HrQoL is captured to a wide extent by
the ICECAP-O, which is consistent with other findings  
[26,27,6368]. The results also confirmed the expected significant
correlation between the ICECAP-O and the ADRQL scores,
which shows that the ICECAP-O captures both generic HrQoL
and dementia specific QoL. Additionally, the correlation between
ADL and ICECAP-O scores reflected that a loss of independence
in ADL was associated with a decline in wellbeing. Decreased
ADL was also associated with lower scores on HrQoL instruments,
confirming previous results that reduced ADL leads to a decrease
in QoL . Overall, these significant findings point in the
direction of favorable convergent validity.
The ICECAP-O discriminated between patients based on the
variables age, dementia severity, care dependency and ADL. This
suggests that the ICECAP-O is sensitive to age differences and to
indicators of health. In a multivariate setting, ICECAP-O scores
were only significantly influenced by ADL, while dementia
severity, care dependency and age were not significant. A possible
explanation for this may be that ADL, dementia severity  and
care dependency are related, while QoL is not necessarily
determined by biological age per se. Dementia severity is one
explanatory variable for the ADL status , which in turn
determines care-dependency . Another explanation for this
finding may be a lack of power to detect all existing relationships
between relevant variables. Indeed, in the bivariate analyses
ICECAP-O scores varied with different dementia severity and
ADL status, supporting discriminant validity of the German
version of the ICECAP-O.
Influences of Proxy Characteristics
That professional or family proxies provide different assessment
of QoL has already been observed in other studies   
. However, specific proxy characteristics such as gender or
work experience were not previously examined in relation to the
ICECAP-O. Our results suggest that nursing professionals gender
and work experience influence their response on the ICECAP-O.
Controlling for residents characteristics, proxy gender and
work experience were related to the ICECAP-O tariff scores. In
absence of a golden standard, it is difficult to judge which proxies
provided the most accurate description of residents QoL. It may
be hypothesized that in assessing QoL, nursing professionals
benefit from more experience with caring for dementia patients.
Male nursing professionals assessed residents QoL significantly
higher than female nursing professionals did, controlling for ADL
status of residents. This difference may either be due to the small
number of questionnaires answered by male nursing professionals,
or by a genuine gender difference in assessing residents QoL. The
relationships between other proxy characteristics and proxy
responses should be explored further in larger samples in future
research. Such research should also address issues of inter-rater
reliability between various proxies, such as professionals and
family members of older people with dementia. Although a golden
standard for the resident population included in this study is
difficult to obtain, by comparing scores of proxies to those of
patients obtained in early stages of dementia, one may perhaps
shed more light on accuracy of QoL assessment of different groups
This study presented the first use of a German version of the
ICECAP-O. The results indicate that the ICECAP-O appears to
be a reliable wellbeing measurement instrument showing good
convergent and discriminant validity for people with dementia.
The influence of proxy characteristics like gender and work
experience suggests potentially fruitful avenues for further
research. In order to confirm the findings of this study, additional
validation studies in larger samples and different settings are
Validating the ICECAP-O as a generic wellbeing instrument
which has the capacity to capture broader outcomes might
contribute to enabling economic evaluation of long-term care
services and interventions, also in Germany. This seems to be
especially relevant for informed decisions in the long-term care
sector where an increase in healthcare spending is expected due to
the growing number of elderly with dementia. In such a setting,
appropriately measuring the potential benefits of care and
comparing them to the costs is pivotal for optimal healthcare
provision. By capturing the relevant outcomes in long-term care,
the ICECAP-O seems to be a suitable wellbeing instrument for
residents with dementia, though further validation work is
The ICECAP-O instrument proxy version.
German version of the ICECAP-O.
We would like to thank the anonymous reviewers for their useful
Conceived and designed the experiments: PM FB. Performed the
experiments: FB. Analyzed the data: PM FB JvE. Wrote the paper: FB
PM WB JvE.
1. McCullagh CD , Craig D , McIlroy SP , Passmore AP ( 2001 ) Risk factors for dementia . Advances in Psychiatric Treatment 7 : 24 - 31 .
2. Prince M , Bryce R , Albanese E , Wimo A , Ribeiro W , et al. ( 2013 ) The global prevalence of dementia: a systematic review and metaanalysis . Alzheimer's & Dementia 9 : 63 - 75 . e62.
3. Verbeek H , Zwakhalen S , van Rossum E , Ambergen T , Kempen G , et al. ( 2010 ) Small-scale, homelike facilities versus regular psychogeriatric nursing home wards: a cross-sectional study into residents' characteristics . BMC Health Services Research 10 : 30 .
4. Coast J , Flynn TN , Natarajan L , Sproston K , Lewis J , et al. ( 2008 ) Valuing the ICECAP capability index for older people . Social science & medicine ( 1982 ) 67: 874 - 882 .
5. Ettema TP , Droes R , de Lange J , Mellenbergh GJ , Ribbe MW ( 2005 ) A review of quality of life instruments used in dementia . Quality of Life Research: An International Journal of Quality of Life Aspects of Treatment, Care & Rehabilitation 14 : 675 - 686 .
6. Drummond MF , Sculpher MJ , Torrance GW , O'Brien BJ , Stoddart GL ( 2005 ) Methods for the economic evaluation of health care programmes . Oxford: Oxford University Press.
7. Hacher J RB ( 2008 ) Die Pflegeversicherung in der Krise - Renditen , Leistungsniveau und Versorgungsl ucken. Koln: Deutsches Institut fur Altersversorge .
8. Jonker C ( 2004 ) A model for quality of life measures in patients with dementia: Lawton's next step . Dementia and geriatric cognitive disorders 18: 159.
9. Robert Koch Institut in Zusammenarbeit mit dem statistischen Bundesamt e (2005) Gesundheitsberichtserstattung des Bundes - Alterdemenz .
10. Bowling A ( 2007 ) Lay theories of quality of life in older age . Ageing and society 27: 827.
11. Cohen-Mansfield J , Marx MS , Dakheel-Ali M , Regier NG , Thein K ( 2010 ) Can persons with dementia be engaged with stimuli? The American journal of geriatric psychiatry: official journal of the American Association for Geriatric Psychiatry 18 : 351 .
12. Cohen-Mansfield J , Dakheel-Ali M , Marx MS ( 2009 ) Engagement in persons with dementia: the concept and its measurement . The American journal of geriatric psychiatry: official journal of the American Association for Geriatric Psychiatry 17 : 299 .
13. Makai P , Brouwer WBF , Koopmanschap MA , Stolk EA , Nieboer AP ( 2014 ) Quality of life instruments for economic evaluations in health and social care for older people: a systematic review Social Science & Medicine 102 : 10 .
14. Brod M , Stewart AL , Sands L , Walton P ( 1999 ) Conceptualization and Measurement of Quality of Life in Dementia: The Dementia Quality of Life Instrument (DQoL) . The Gerontologist 39 : 25 - 36 .
15. Ettema TP , Droes RM , de Lange J , Mellenbergh GJ , Ribbe MW ( 2007 ) QUALIDEM: development and evaluation of a dementia specific quality of life instrument-validation . International journal of geriatric psychiatry 22 : 424 - 430 .
16. Ready RE , Ott BR , Grace J , Fernandez I ( 2002 ) The Cornell-Brown Scale for Quality of Life in Dementia . Alzheimer Disease & Associated Disorders 16 : 109 - 115 .
17. Selai CCE ( 2001 ) Assessing quality of life in dementia: Preliminary psychometric testing of the Quality of Life Assessment Schedule (QOLAS) . Neuropsychological rehabilitation 11 : 219 - 243 .
18. Rabins PV ( 2007 ) Measuring quality of life in dementia: purposes, goals, challenges and progress . International psychogeriatrics 19: 401.
19. Perales J , Cosco TD , Stephan B , Haro JM , Brayne C ( 2013 ) Health-related quality-of-life instruments for Alzheimer's disease and mixed dementia . International Psychogeriatrics: 1 - 16 .
20. Schram MT , Frijters D , van de Lisdonk EH , Ploemacher J , de Craen AJ , et al. ( 2008 ) Setting and registry characteristics affect the prevalence and nature of multimorbidity in the elderly . Journal of clinical epidemiology 61 : 1104 - 1112 .
21. Makai P ( 2012 ) Capabilities and quality of life in Dutch psycho-geriatric nursing homes: an exploratory study using a proxy version of the ICECAP-O . Quality of life research 21 : 801 - 812 .
22. Al-Janabi H , N Flynn T, Coast J ( 2011 ) Development of a self-report measure of capability wellbeing for adults: the ICECAP-A. Quality of Life Research .
23. Sen A ( 1982 ) Choice, welfare and measurement . Cambridge, MA: Harvard University Press.
24. Grewal I , Lewis J , Flynn T , Brown J , Bond J , et al. ( 2006 ) Developing attributes for a generic quality of life measure for older people: Preferences or capabilities? Social Science and Medicine 62 : 1891 - 1901 .
25. Coast J , Peters TJ , Natarajan L , Sproston K , Flynn T ( 2008 ) An assessment of the construct validity of the descriptive system for the ICECAP capability measure for older people . Quality of life research : an international journal of quality of life aspects of treatment, care and rehabilitation 17 : 967 - 976 .
26. Couzner L , Ratcliffe J , Lester L , Flynn T , Crotty M ( 2012 ) Measuring and valuing quality of life for public health research: application of the ICECAP-O capability index in the Australian general population . International Journal of Public Health : 1 - 10 .
27. Davis JC , Bryan S , McLeod R , Rogers J , Khan K , et al. ( 2012 ) Exploration of the association between quality of life, assessed by the EQ-5D and ICECAP-O, and falls risk, cognitive function and daily function, in older adults with mobility impairments . BMC Geriatrics 12 : 65 .
28. Pickard AS , Knight SJ ( 2005 ) Proxy evaluation of health-related quality of life: a conceptual framework for understanding multiple proxy perspectives . Medical care 43 : 493 - 499 .
29. 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 : 760 - 771 .
30. Ankri JJ ( 2003 ) Use of the EQ-5D among patients suffering from dementia . Journal of clinical epidemiology 56 : 1055 - 1063 .
31. Novella JL , Jochum C , Jolly D , Morrone I , Ankri J , et al. ( 2001 ) Agreement between patients' and proxies' reports of quality of life in Alzheimer's disease . Quality of Life Research: An International Journal of Quality of Life Aspects of Treatment, Care & Rehabilitation 10 : 443 - 452 .
32. Bryan S , Hardyman W , Bentham P , Buckley A , Laight A ( 2005 ) Proxy completion of EQ-5D in patients with dementia . Quality of Life Research: An International Journal of Quality of Life Aspects of Treatment, Care & Rehabilitation 14 : 107 - 118 .
33. Kasper JD , Black BS , Shore AD , Rabins PV ( 2009 ) Evaluation of the validity and reliability of the Alzheimer Disease-related Quality of Life Assessment Instrument . Alzheimer Disease and Associated Disorders 23 : 275 - 284 .
34. Bundesministerium fu r G Demenz: Eine Herausforderung fu r die Gesellschaft .
35. Weyerer SS ( 2004 ) Die Versorgung dementer Patienten in Deutschland ausepidemiologischer Sicht . Zeitschrift fu r Gerontopsychologie & -psychiatrie 17 : 41 - 50 .
36. GKV-Spitzenverband ( 2009 ) Richtlinien des GKV-Spitzenverbandes zur Begutachtung von Pflegebedu rftigkeit nach dem XI. Buch des Sozialgesetzbuches . Berlin.
37. Deutsches Institut fu r Medizinische Dokumentation und I ICD-10-GM Vorabversion 2012 .
38. Deutsche Gesellschaft fu r Neurologie DGfPPuN (2009) S3- Leitlinie - ' 'Demenzen'' (Kurzversion).
39. Ready RE , Ott BR ( 2008 ) Integrating patient and informant reports on the Cornell-Brown Quality-of-Life Scale . American Journal of Alzheimer's Disease and Other Dementias 22 : 528 - 534 .
40. Missotten P ( 2008 ) Relationship between quality of life and cognitive decline in dementia . Dementia and geriatric cognitive disorders 25: 564.
41. Rabins PV , Kasper JD , Kleinman L , Black BS ( 1999 ) Conxepts and Methods in the Development of the ADRQLD: an Instrument for Asessing Health-Related Quality of Life in Persons with Altzheimer Disease . Journal of Mental Health and Ageing 5 : 33 .
42. Menzi-Kuhn C ( 2006 ) Lebensqualitat von Menschen mit Demenz in stationaren Langzeitpflegeeinrichtungen . Maastricht: University of Maastricht.
43. Black BS , Rabins PV , Kasper JD ( 2009 ) Alzheimer Disease Related Quality of Life User's Manual . Baltimore, Maryland.
44. Sloane PPD ( 2005 ) Evaluating the Quality of Life of Long-Term Care Residents With Dementia . The Gerontologist 45 : 37 - 49 .
45. Gonzalez-Salvador T , Lyketsos CG , Baker A , Hovanec L , Roques C , et al. ( 2000 ) Quality of life in dementia patients in long-term care . International journal of geriatric psychiatry 15 : 181 - 189 .
46. Lyketsos CCG ( 2003 ) A follow-up study of change in quality of life among persons with dementia residing in a long-term care facility . International journal of geriatric psychiatry 18 : 275 - 281 .
47. The EuroQol G ( 1990 ) EuroQol-a new facility for the measurement of healthrelated quality of life. Health policy (Amsterdam , Netherlands) 16 : 199 - 208 .
48. Greiner WW ( 2005 ) Validating the EQ-5D with time trade off for the German population . The European journal of health economics 6 : 124 - 130 .
49. Kunz SS ( 2010 ) Psychometric properties of the EQ-5D in a study of people with mild to moderate dementia . Quality of life research 19 : 425 - 434 .
50. Wolfs CA , Dirksen CD , Kessels A , Willems DC , Verhey FR , et al. ( 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.
51. Krabbe PPFM ( 1999 ) The Effect of Adding a Cognitive Dimension to the EuroQol Multiattribute Health-Status Classification System . Journal of clinical epidemiology 52 : 293 - 301 .
52. Greiner W , Claes C ( 2007 ) Der EQ-5D der EuroQol-Gruppe . In: Scho ffski O, Schulenburg JMG, editors. Gesundheitso konomische Evaluationen : Springer Berlin Heidelberg. 403 - 414 .
53. Andersen CCK ( 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: 52.
54. Kwasky AN , Harrison BE , Whall AL ( 2010 ) Quality of Life and Dementia: An Integrated Review of Literature . Alzheimer's Care Today 11 : p 186 - 195 .
55. Mahoney FI , Barthel DW ( 1965 ) Functional Evaluation: the Barthel Index . Md State Med J 14 : 61 - 65 .
56. Collin CC ( 1988 ) The Barthel ADL Index: A reliability study . Disability and rehabilitation 10 : 61 - 63 .
57. Berliner Schlaganfall A Medizinische Rehabilitation nach Schlaganfall .
58. Heuschmann PPU ( 2005 ) Untersuchung der Reliabilitat der deutschen Version des Barthel-Index sowie Entwicklung einer postalischen und telefonischen Fassung fu r den Einsatz bei Schlaganfall-Patienten . Fortschritte der Neurologie, Psychiatrie 73 : 74 - 82 .
59. Cohen J ( 1988 ) Set Correlation and Contingency Tables . Applied Psychological Measurement 12 : 425 - 434 .
60. Graske J , Fischer T , Kuhlmey A , 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 : 819 - 827 .
61. Voigt-Radloff S , Leonhart R , Schu tzwohl M , Jurjanz L , Reuster T , et al. ( 2012 ) Dementia quality of life instrument-construct and concurrent validity in patients with mild to moderate dementia . European Journal of Neurology 19 : 376 - 384 .
62. Bartholomeyczik S , Nordheim J , Achterberg W , Halek M ( 2011 ) Validity, reliability, and feasibility of a quality of life questionnaire for people with dementia . Zeitschrift fur Gerontologie und Geriatrie 44 : 405 - 410 .
63. Coast J , Peters TJ , Natarajan L , Sproston K , Flynn T ( 2008 ) An assessment of the construct validity of the descriptive system for the ICECAP capability measure for older people . Quality of Life Research: An International Journal of Quality of Life Aspects of Treatment, Care & Rehabilitation 17 : 967 - 976 .
64. Makai P , Koopmanschap MA , Brouwer WBF , Nieboer AP ( 2013 ) A validation of the ICECAP-O in a population of post-hospitalized older people . Health and Quality of Life Outcomes 11 : 1 - 11 .
65. Couzner L , Ratcliffe J , Crotty M ( 2012 ) The relationship between quality of life, health and care transition: an empirical comparison in an older post-acute population . Health and Quality of Life Outcomes 10 : 69 .
66. Davis JC , Liu-Ambrose T , Richardson CG , Bryan S ( 2011 ) A comparison of the ICECAP-O with EQ-5D in a falls prevention clinical setting: are they complements or substitutes ? Quality of Life Research: 1-9.
67. Mitchell PM , Roberts TE , Barton PM , Pollard BS , Coast J ( 2013 ) Predicting the ICECAP-O Capability Index from the WOMAC Osteoarthritis Index Is Mapping onto Capability from Condition-Specific Health Status Questionnaires Feasible? Medical Decision Making .
68. Comans TA , Peel NM , Gray LC , Scuffham PA ( 2013 ) Quality of life of older frail persons receiving a post-discharge program . Health and Quality of Life Outcomes 11 : 58 .
69. Carpenter CR , Bassett ER , Fischer GM , Shirshekan J , Galvin JE , et al. ( 2011 ) Four sensitive screening tools to detect cognitive dysfunction in geriatric emergency department patients: Brief Alzheimer's screen, short blessed test, Ottawa 3DY, and the caregiver-completed AD8 . Academic Emergency Medicine 18 : 374 - 384 .
70. Albert SM ( 1999 ) Proxy-reported quality of life in Alzheimer's patients: Comparison of clinical and population based samples . J Ment Health Aging 5 : 49 - 68 .