• Alzheimer disease;
  • caregiver;
  • dementia;
  • dependency;
  • quality of life


  1. Top of page
  2. Abstract

Abstract  A qualitative tool was recently developed for evaluation of dependency in a demented population. This tool assesses the impact of cognitive impairment on functional status, taking into account disability in both the basic and the instrumental activities of daily living. The purpose of the present paper was to study the impact of dependency on informal caregivers who assist demented patients at home, with this new useful tool. Methods: A cross-sectional analysis was undertaken of the subgroup of 145 demented patients of the National Dementia Economic Study, aged ≥65 years, living in the community, with an available caregiver. A neuropsychological assessment of patients (Mini-Mental State Examination) and a comprehensive evaluation of caregivers (quality of life, Short Form Health Survey-36, depression, Sense of Competence) were recorded. A total of 32.4% were dependent, disabled in both basic and instrumental functions, 42.1% were non-dependent but with instrumental functional disabilities and 25.5% were non-dependent. Impact of dependency on the caregiver's experience was significant for different aspects (satisfaction with caregiving, subjective burden, quality of life, depression). Medical and non-medical costs increased with the severity of functional disability. Findings indicate that this tool is also useful to assess the impact of progression of functional disability in patients with dementia, on the caregiver issues. The consequences appeared both on personal feelings and on quality of life and financial involvement in management of the patient. Cognitive impairment appears to have more moderate repercussions in these areas.


  1. Top of page
  2. Abstract

Dementia is a progressive disorder accompanied by a gradual loss of independence. The level of dependency is therefore an important outcome to be measured in demented patients in order to evaluate the impact of cognitive impairment on functional status and the need for care. Because there is no cure for dementia, it is also essential to be able to accurately evaluate the effects of treatment on these outcomes.1 For example, placement is largely influenced by a level of dependency that cannot be sustained by caregiving at home,2 and this outcome is an important element to be included in research of the effectiveness of therapies. A simple criterion for loss of independence would also make the results of the various research studies, notably in terms of medico-economic evaluation, clearer and more easily understandable for decision-makers.

Evaluation of disability in daily living is classically based on the administration of a battery of tests that measure difficulty in performing instrumental3 and basic activities of daily living (IADL and basic ADL).4 Recently, Kurz et al. developed a tool for evaluation offunctional disability in dementia that takes into account disability in both the basic ADL and the IADL and which is correlated with the severity of the patient's cognitive impairment, sociodemographic characteristics and the cost of management.5 We wished to study the impact of dependency, defined by the Kurz et al. classification, on the life of the informal caregiver taking charge of a demented patient at home. We were interested only in informal caregivers, who would be more at risk of depression.6


  1. Top of page
  2. Abstract

Study population

The National Dementia Economic Study (NADES) is a prospective, 1-year cohort study developed to assess the socioeconomic consequences of dementia in Belgium. The initial enrollment in NADES has been described previously.7,8 In that study the functional status of the patient was recorded at the 6-month visit for 266 patients, of whom 156 were community-dwelling. Eleven of these 156 patients had no identifiable caregiver and were excluded from the analysis.

The present study is a cross-sectional analysis of the subgroup of 145 demented patients, aged ≥65 years, living in the community, with an available caregiver. Data describing patient and caregiver characteristics were collected at 6 months.

Data collection

Clinical, quality of life (QOL) and socioeconomic data were collected at 6 months from various sources. The patient himself/herself (or an informant) and a caregiver if available were interviewed at home or by telephone by a trained psychologist. Clinical data and use of health services were also collected by the clinical investigator (primary care physician or specialist).

Patient data

Patient data consisted of (i) sociodemographic information (age, gender); (ii) cognitive function with the Mini-Mental State Examination (MMSE);9 (iii) economic data concerning direct and indirect costs (evaluation of medical costs was based on the following information: visits to GPs and specialists, physiotherapy, nursing care, hospitalizations, incontinence and medications; evaluation of non-medical costs was based on use of services [special food, laundry], professional help [household assistance, social help], non-professional help and caregiving, these data were provided by the patients themselves or their caregiver, for each item the total cost and the respective costs for the health system and for the patient were calculated); and (iv) qualitative evaluation of functional disability in dementia,5 which corresponds to an automatic classification of the patients from ADL4 and IADL scales.3

Caregiver data

Caregiver data consisted of (i) sociodemographic information (age, gender, cohabitation with the patient); (ii) generic QOL with the Dartmouth Primary Care Cooperative Information Functional Health Assessment/ World Organization Project of National Colleges and Academics (COOP/WONCA) charts;10 (iii) Short Form Health Survey-36 (SF-36); (iv) depression with the Beck Depression Inventory;11 and (v) psychological burden of caring for the demented patient assessed by the Sense of Competence Questionnaire (SCQ).12 The value of this scale is to take into account both the positive and negative consequences of caregiving. It can be useful in practice to evaluate the tolerance threshold of caregivers and to identify those at risk of burnout. A short seven-item version has been validated for routine use in practice by general practitioners. These items also cover the three domains of satisfaction with the elderly person as a recipient of care, satisfaction with one's own performance as a caregiver, and consequences of involvement in care for the personal life of the caregiver.13

Statistical analysis

In order to qualitatively evaluate functional disability, we performed an automatic classification of the patients using the nearest centroid sorting,14 a clustering method derived from the McQueen's k-means method. This method is based upon a concept of seeds, wherein each patient is assigned to the cluster with the nearest seed. Such methods have already been used in the field of dementia15,16 because they permit the sorting of patients by simultaneously considering their scores on various scales. The nearest centroid sorting method has demonstrated excellent results compared to other clustering methods.17

The sociodemographic characteristics of patients and caregivers were described, first in the whole study population and then by disability group by providing mean and standard deviations for quantitative parameters and percentages for qualitative parameters. These characteristics were then compared between the disability groups using the Kruskal–Wallis test for quantitative parameters and the χ2 test for qualitative parameters. The QOL scores and costs were described by disability and severity groups by providing mean and standard deviations and compared between groups with the Kruskal–Wallis test. We performed all statistical analysis, with a significance level of 0.05, using SAS version 8.2 software (SAS Institute, Cary, NC, USA).


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  2. Abstract

One hundred and forty-five caregiver–patient dyads completed the questionnaire. Table 1 shows the sociodemographic characteristics of patients and caregivers at the 6-month visit. Patients aged 78.6 ± 6.9 years cohabited in 78.6% of cases with a caregiver. These caregivers were women in 66.9% of cases, mean age 66.4 ± 12.8 years, the majority being spouses and more rarely adult children or other persons in the immediate circle (brothers, sisters, nephews, nieces, friends).

Table 1.  Characteristics of patients and their caregivers at 6 months after inclusion (n = 145)
 n (%)
  1. IFD, instrumental functional disability; MMSE, Mini-Mental State Examination.

Patient characteristics
 Female96 (66.2)
 Male49 (38.8)
Time since first symptoms (years), mean ± SD 3.8 ± 2.9
Time since diagnosis (years), mean ± SD 2.4 ± 2.4
MMSE (mean ± SD)15.4 ± 8.9
Severity of cognitive impairment
 Mild (MMSE > 20)52 (36.4)
 Moderate (MMSE 15–20)35 (24.5)
 Moderately severe (MMSE 10–14)16 (11.2)
 Severe (MMSE < 10)40 (27.9)
Level of disability
 Non-dependent47 (32.4)
 Non-dependent-IFD61 (42.1)
 Dependent37 (25.5)
Level of education
 Primary school96 (67.1)
 Secondary school40 (28.0)
 Other (technical school, university . . .)7 (4.9)
Income (euros, monthly)
 <5007 (4.8)
 500–100078 (53.8)
 1000–150035 (24.1)
 >150013 (9.0)
 Unknown3 (2.1)
 Missing9 (6.2)
Caregiver characteristics
Relationship to patient
 Spouse77 (53.1)
 Child37 (25.5)
 Other31 (21.4)

Concerning the severity of cognitive impairment, based on their MMSE score, 36.4% of patients had mild, 24.5% mild–moderate, 11.2% moderate to moderately severe and 27.9%, severe dementia.

Patients were divided into three disability groups according to the Kurz classification: 32.4% were dependent, that is, severely disabled in both basic and instrumental functions, 42.1% were non-dependent but with instrumental functional disabilities (i.e. severely disabled in instrumental functions but their basic functions were still fairly intact), and 25.5% were non-dependent, showing little deterioration in instrumental functions and with their basic functions practically intact.

The sociodemographic characteristics of the patient–caregiver pairs showed little difference according to level of dependency (Table 2). There was a non-significant tendency towards cohabitation with the caregiver as functional disability worsened. The degree of kinship of the caregiver did not appear to differ between groups but caregivers who were not spouses or adult children tended to care for subjects who had fewer difficulties with ADL. There was a significant association between the functional level and the cognitive function with this new tool. Association with ADL and IADL scales separately is significant, having a coefficient of correlation with MMSE of 0.56 (P < 0.001) and 0.57 (P < 0.001), respectively.

Table 2.  Characteristics according to the level of functional dependency (n = 145)
n = 47n = 61n = 37
  1. ND-IFD, not dependent–instrumental functional disability; MMSE, Mini-Mental State Examination.

Patient characteristics
Age (years), mean ± SD77.8 ± 5.678.4 ± 7.280.1 ± 7.70.358
Time since first symptoms (years), mean ± SD3.1 ± 2.43.7 ± 2.84.6 ± 3.20.230
Time since diagnosis (years), mean ± SD2.0 ± 2.42.3 ± 2.23.3 ± 2.70.090
MMSE, mean ± SD21.4 ± 5.214.7 ± 8.59.1 ± 8.5<0.001
Level of education
 Primary school3678.33456.72670.30.421
 Secondary school919.62135.01027.0 
Income (euros, monthly)
Caregiver characteristics
Age (years), mean ± SD66.9 ± 14.365.7 ± 12.467.0 ± 11.80.672
Caregiver gender
Relationship to patient

Table 3 summarizes the impact of dependency on the caregiver's experience in different dimensions: satisfaction with caregiving, subjective burden, QOL, depression. All the dimensions investigated were associated with the level of dependency.

Table 3.  Impact of the level of functional dependency on the caregiver's personal life
n = 47n = 61n = 37
  1. COOP, Dartmouth Primary Care Cooperative Information Functional Health Assessment; ND-IFD, not dependent–instrumental functional disability; MMSE, Mini-Mental State Examination; WONCA, World Organization Project of National Colleges and Academics.

Specific quality of life
Sense Competence Questionnaire
 Satisfaction with the patient5.75 ± 1.465.55 ± 1.905.50 ± 1.870.9309
 Satisfaction with one's performance8.46 ± 2.788.28 ± 2.707.53 ± 2.830.3487
 Consequences for personal life5.24 ± 2.243.68 ± 2.452.76 ± 2.380.0002
 Total19.55 ± 4.9617.57 ± 5.7816.16 ± 4.850.0420
Depression (Beck)3.96 ± 3.674.43 ± 4.736.36 ± 4.320.0288
Generic quality of life
Short Form Health Survey-36
 Pain index66.66 ± 30.2170.93 ± 31.8161.24 ± 30.810.3481
 General health65.87 ± 18.5861.58 ± 24.7553.28 ± 22.840.0917
 Mental health63.26 ± 20.6259.33 ± 20.1154.29 ± 23.080.2253
 Physical functioning74.32 ± 24.2467.96 ± 32.5665.28 ± 25.410.4252
 Role-emotional71.49 ± 40.0767.90 ± 41.9567.82 ± 42.240.9005
 Role-physical71.71 ± 38.1967.13 ± 41.4457.76 ± 41.240.2782
 Social functioning86.18 ± 19.6775.93 ± 30.7060.78 ± 30.020.0042
 Vitality56.97 ± 20.5249.23 ± 25.3446.96 ± 23.470.1003
 Daily activities1.84 ± 0.932.18 ± 1.362.50 ± 1.220.1052
 Social activities1.57 ± 0.961.93 ± 1.332.70 ± 1.510.0039
 Change in health2.94 ± 0.243.00 ± 0.513.07 ± 0.580.2366
 Physical fitness3.32 ± 1.063.20 ± 1.113.77 ± 1.280.0503
 Feelings2.00 ± 1.031.96 ± 1.322.50 ± 1.280.0932
 Overall health2.84 ± 0.762.91 ± 1.043.20 ± 0.850.1385

On the SCQ, the total score significantly worsened as functional disability increased (P = 0.0420). Analysis of the different dimensions of this score shows that this was due to the dimensions that evaluate the negative consequences of caring on the caregiver's life. The dimensions that evaluate the satisfaction related to caring seemed to be less correlated with the severity of functional disability.

The score on the Beck scale reflects increasing depression of the caregiver in parallel to increasing disability of the care recipient (P = 0.0288).

Concerning the caregiver's QOL, the two generic tools used in the present study were also correlated with dependency. QOL measured with the SF-36 showed a significant decrease for the social functioning dimension, reflecting a poorer QOL (P = 0.0042). QOL measured with the COOP/WONCA scale gave an increased score, also reflecting poorer QOL as the care recipient became more disabled, in two dimensions: social activities (P = 0.0039) and physical fitness (P = 0.0503). The other dimensions exploring feelings, daily activities, change in health and overall health did not appear to be related to level of dependency.

It is interesting to note that the impact of disease severity on the caregiver depended on the level of disability. The severity of cognitive impairment appeared to have less impact on the caregiver's experience than the severity of functional disability. In fact, only the dimension exploring the consequences of caregiving on the life of the caregiver was correlated with the severity of cognitive impairment (Table 4).

Table 4.  Impact of severity of cognitive impairment on the caregiver's personal life
 MildModerateModerately SevereSevereP
n = 52n = 35n = 16n = 40
  1. COOP, Dartmouth Primary Care Cooperative Information Functional Health Assessment; WONCA, World Organization Project of National Colleges and Academics.

Specific quality of life
Sense competence questionnaire
 Satisfaction with the patient6.04 ± 1.335.04 ± 1.945.21 ± 2.435.57 ± 1.770.2075
 Satisfaction with one's performance8.65 ± 2.657.64 ± 2.977.97 ± 3.518.00 ± 2.470.5052
 Consequences on personal life4.81 ± 2.433.34 ± 1.973.60 ± 2.923.42 ± 2.630.0373
 Total19.58 ± 4.5516.03 ± 5.8717.05 ± 7.4517.30 ± 4.910.0978
Depression (Beck)4.29 ± 4.095.16 ± 4.794.70 ± 5.775.03 ± 4.210.7620
Generic quality of life
Short Form Health Survey-36
 Pain index65.04 ± 32.4661.33 ± 31.5176.50 ± 26.0972.67 ± 30.690.3427
 General health65.38 ± 21.3756.78 ± 23.2856.50 ± 26.1659.11 ± 23.400.3697
 Mental health60.45 ± 22.5553.48 ± 21.9758.00 ± 17.4462.17 ± 19.140.4431
 Physical functioning68.89 ± 28.7066.35 ± 28.0670.00 ± 37.6070.81 ± 26.880.8019
 Role-emotional69.26 ± 42.0461.73 ± 43.0777.78 ± 38.4969.52 ± 40.720.6991
 Role-physical66.67 ± 41.6362.04 ± 40.0572.92 ± 41.9166.43 ± 40.650.8207
 Social functioning77.22 ± 30.5474.54 ± 30.1280.21 ± 22.9071.43 ± 28.690.6432
 Vitality51.02 ± 25.2148.70 ± 22.6050.83 ± 27.3752.52 ± 22.220.9119
 Daily activities2.04 ± 1.172.22 ± 1.311.83 ± 1.032.42 ± 1.300.4684
 Social activities1.82 ± 1.272.11 ± 1.421.75 ± 1.142.22 ± 1.420.4528
 Change in health2.95 ± 0.482.92 ± 0.693.17 ± 0.393.06 ± 0.240.4500
 Physical fitness3.33 ± 1.133.48 ± 1.163.08 ± 1.163.44 ± 1.230.6719
 Feelings2.04 ± 1.282.37 ± 1.391.75 ± 0.972.11 ± 1.170.6179
 Overall health2.89 ± 0.913.11 ± 0.973.17 ± 0.942.89 ± 0.920.4946

The cost of home management of a demented patient (medical costs, non-medical costs) increased overall by 160% with the severity of functional disability, while the increase was less marked with the severity of cognitive impairment. The costs incurred by the patient and his or her relatives (non-medical costs) increased from the onset of the first difficulties in ADL and represented more than 20% of overall costs (Figs 1,2).


Figure 1. Impact of the severity of cognitive impairment on cost of management.

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Figure 2. Impact of the severity of functional disability on cost of management. ND-IFD, not dependent–instrumental functional disability.

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  1. Top of page
  2. Abstract

Our findings indicate that the progression of functional disability in patients with dementia has a significant impact on the caregiver, both on his or her personal feelings (satisfaction with care, depression) and on QOL and financial involvement in management of the patient. Even if there is a significant association between the functional level and the cognitive impairment, the level of cognitive impairment appears to have more moderate repercussions in these areas. It can be explained by the fact that the QOL of caregivers depends on the difficulties encountered daily and because the majority of caregivers live with the patient in the present study, they doubtless are very involved in basic ADL and IADL. In addition, it has been shown that more than the level of cognitive functions, the diagnosis of the dementia is disturbing for informal caregivers.18,19

Concerning the caregiver's QOL, our findings demonstrate that the patient's functional dependency is associated with certain of its dimensions. Caregivers of very dependent persons experience a diminished QOL because of the repercussions of their role on their social life. Earlier works have already shown that caregivers of demented patients more often complain of limited social life than those of non-demented persons.20 This finding supports the concept that QOL is a very pertinent indicator for caregiver assessment in cohorts of demented patients.21 We observed no difference in QOL related to the caregiver's physical health, whereas feelings of depression increased with functional disability. These results corroborate those of the literature, which stress the repercussions of caregiving on the mental rather than the physical health of the caregiver. Caregivers suffer from depression more frequently than the general population of the same age22 and are more likely to use psychotropic drugs.23 Longitudinal follow up also reports increased frequency of psychological symptoms but not of physical signs,24 and a risk of depression at 1 year, which is twice as high in caregivers, while their physical health remains unchanged.25

Using the SCQ, we observed that the burden of caregiving, but not the reward, was related to the level of dependency. It would seem that reward is linked with factors specific to the caregiver and correlated withfactors other than the severity of the patient's functional disability. Possibly, factors that were not explored, such as the quality of the earlier relationship between caregiver and patient, strongly influence this positive experience. Caregiving is considered positive by the caregiver if it is linked with a feeling of satisfaction, if it strengthens the links between caregiver and care recipient,26 or if it has a structuring role for the caregiver who has the feeling of accomplishing a difficult task.27 These positive aspects of caregiving that are observed within couples may be in part explained by the fact that closeness and interaction between spouses are long preserved and continue to provide the caregiver with satisfaction even if the spouse is affected by dementia.28 Thus this caring relationship does not appear on neutral ground, whatever the degree of kinship of the caregiver.29 In an investigation of the factors associated with caregiver stress, Cantor found that the most closely associated factor was by far the degree of kinship between caregiver and care recipient, as well as the quality of the relationship between them.30

Last, we show that the cost of management at home of a demented patient increases with the severity of functional disability where medical costs are concerned, as do the non-medical costs that are incurred by the patient and his or her relatives. The cost of informal aid was not taken into account in the present study, but it is important to estimate this resource because according to demographic predictions, such aid is expected to decrease in the coming years and will have to be replaced by professional care.31 Depending on the studies, informal care represents 36–85% of total cost.32,33

We have shown that the severity of cognitive impairment and the severity of functional disability did not have the same repercussions on the caregiver's life. These findings corroborate those of other studies.34,35 In particular, one study carried out in a population of demented patients showed that among the subjects who needed a high level of assistance comparable with that received in an institution (full-time care), none of the classic markers of disease severity (Mini-Mental State Examination, Blessed Dementia Rating Scale, Clinical Dementia Rating) was linked with placement. These results suggest that the cognitive impairment of dementia no longer adequately explains recourse to institutionalization as soon as the patient requires considerable assistance.36

A strong point of the present study on the methodological level is that it is population based.7 Studies in which caregiver samples are recruited from the general population are rare because there is no exhaustive census of these persons and setting up such studies requires complex logistics. Generally, caregivers are recruited from the files of assistance and home care services or support groups. Caregivers who have never been in contact with assistance or care services have little chance of being included in research, and these studies are not representative of caregivers as a whole.37

Moreover, caregivers recruited from support groups may be expected to possess specific characteristics that do not allow generalization of the results. It appears in fact that those caregivers who refuse to take part in research take care of more dependent persons.38 Lack of time and resources are frequent reasons for refusing to participate.39 Also, there may well be a certain selection bias linked to the recruitment of caregiver–care recipient dyads some time after the disease has been diagnosed, and so some time after the caregiver has taken on the caring role. This may overrepresent the more stable situations because the more fragilecaregivers may from the beginning have refused to take care of the person or may have very soon resorted to institutional placement.

A limitation of the present study remains the non-inclusion of certain variables such as behavioral disturbance, which are known to be associated with the severity of the disease and to have important repercussions on the caregiver's life.25,40 The knowledge of behavioral disturbance contributes to better characterizing a population of demented persons. However, in order to assess behavioral disturbance, we need to ask the caregivers, and behavioral disturbance and caregiver QOL should be linked.41

In conclusion, the tool for evaluation of dependency as defined by Kurz et al. can also be used to study the repercussions of caring on the caregiver. Recent studies emphasize the need to take the caregiver dimension into account in interventions directed at demented patients.42 In addition, it makes it possible to distinguish groups of patients according to cost of management. In view of the predicted demographic evolution, all measures likely to reduce the cost of care must be examined.43


  1. Top of page
  2. Abstract
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