Based on the SoCA-Dem theory [15], we identified the underlying structures of differences and commonalities of home-based care arrangements for persons living with dementia. Thus, this study is the first attempt to operationalise the concepts of this theory into measurable variables. Building on these underlying structures, we distinguished four types of home-based care arrangements and compared them with regard to their stability. The four identified types explained 24.08% of the variance between the care arrangements in our sample. This means that there is still a high percentage of variance within the types (75.92%); therefore, the identified types must not be mistaken as being homogenous (see Table 6 and Additional file 1: Appendix E).
‘Dementia and care trajectory’ and ‘structure of the dyadic relationship’ are the two axes that best distinguish care arrangements from each other. The first axis highlights the importance of temporality and change in caring, which is often not adequately recognised in research [34]. Both spouse-centred types and, to a smaller degree, both child-centred types differ significantly from each other with regard to the variables of the SoCA-Dem concept ‘change’. This axis also shows that informal carers in later stages report personal constraints and a loss of relationship with the person with dementia more frequently than informal carers at the earlier stages. However, they also report personal growth more frequently. These relationships were also confirmed in a study by Zank and Schacke [35]. Depending on the position on the ‘dementia and care trajectory’, persons with dementia and informal carers differ in their needs [10, 36, 37], which must be recognised to be able to offer tailored support. In sum, the difference between the two spouse-centred types and between the two child-centred types is grounded mainly in their position on the axis ‘dementia and care trajectory’. Therefore, the question arises whether both ‘earlier’ types will make a transition to become ‘later’ types over the course of time. It is likely that the care dependency as well as the cognitive and functional impairment of the persons with dementia will increase, and the role of the informal carers will change accordingly. Therefore, the care arrangements of both ‘earlier’ types will probably share an increasing number of characteristics with the care arrangements of the ‘later’ types and therefore could transition to the other types. However, not all care arrangements of the earlier types continue long enough to make this transition. For example, 24.05% of persons with dementia of the type ‘child-centred earlier’ moved to an institutional form of living and 7.6% died over the course of one year. The possibility that carers make a transition to other types has also been discussed in other research papers [38, 39]. Since these studies and our study constructed types on the basis of cross-sectional data, the question of transitions between different types cannot be conclusively answered. Therefore, these studies and our results stress the importance of longitudinal research to be able to comprehensively describe and understand care arrangements and their development over time.
The second axis, ‘structure of the dyadic relationship’, separates care arrangements in which the carer is the spouse of the person with dementia from care arrangements in which the carer is an adult child or another family member. Other sociodemographic variables accompany this separation: adult child carers and other family members more often do not live together with the person with dementia, are more often younger than 65 years, and work. The person with dementia for whom they care is often older than 80 years and female. The distinction of care arrangements on the basis of the kinship relation between the carer and the person with dementia is common in research [40, 41]. In addition, our findings show that many other sociodemographic differences accompany this distinction. Expectedly, spouses and adult child carers seem to experience and organise care arrangements differently, which becomes apparent with regard to their stability.
Based on the first 15 axes of MCA, we distinguished four different types of home-based care arrangements. Because the first two axes explained most of the variance, we derived the names of the types from these two axes. Through our naming, we put the main informal carer in the centre of the care arrangements. Although one informal carer often bears the main responsibility of a care arrangement for a person with dementia, our naming could conceal the fact that more persons from the social network, professional carers, and the person with dementia herself/himself often play important roles in these care arrangements [42]. We have already critically discussed this narrow focus on the perspective of one informal carer during the development of our middle-range theory of stability [15]. Nevertheless, our naming of the types affirms this narrow focus instead of expanding it to include, e.g., family dynamics [43] or the perspective of the person with dementia [44] or professional carers [45]. In future research, additional perspectives should be recognised to investigate their impact on the construction of types of care arrangements.
According to our definition of stability, home-based care arrangements are stable if the person with dementia can stay at home and his or her needs and the needs of the informal carer are addressed adequately [11]. The four types of care arrangements differ with regard to the chosen indicator variables for stability. Although the care dependency of the person with dementia and role conflicts of the informal carer in the type ‘child-centred earlier’ are rather low and the care arrangements exist rather briefly, 24.05% of persons with dementia in these care arrangements moved to an institutional form of living within one year. The high rate of institutionalisation in this type is not necessarily an indicator of instability [11]. If the transition to a nursing home is well planned, it might be in the interest of the person with dementia as well as the informal carer [46]. One reason for the high rate of institutionalisation might be that 62% of the persons with dementia in this type live alone, which has been identified as a risk factor for institutionalisation [47] and crises [48]. Persons with dementia often need a high amount of supervision [49], which informal carers who do not share the same household might not be willing or able to provide. In light of the growing spatial distance between informal carers and persons in need of care [50], high integration of women into the workforce and decreasing birth rates in modern societies, the willingness and ability to care might further decrease [51]. A higher utilization of formal support in care arrangements for persons with dementia living alone might be a substitute for the temporary unavailability of the informal carers in these care arrangements [52]. One form of formal support that makes large periods of supervision possible is 24-h live-in carers. Recently, the German Federal Labour Court ruled that live-in carers have a right to the minimum wage even for times of standby duty, which means that they are unaffordable for many families [53]. These societal changes emphasise that the sociocultural context of caring must be taken into account to understand home-based care arrangements for persons with dementia and to support their stability in the best possible way [54]. The SoCA-Dem theory, with its concepts ‘health care system’ and ‘society and culture’ (see Fig. 1), provides a suitable frame for conducting research with this aspiration [15].
In the ‘child-centred later’ type, the rate of institutionalisation over one year was lower (17.91%), although the care dependency and cognitive/functional impairment of the persons with dementia was much higher and the role conflicts of the informal carers were much larger than those of the ‘child-centred earlier’ type. Furthermore, many informal carers of the ‘child-centred later’ type experienced a lack of institutional support, which suggests that supporting a person with dementia living at home is achieved at high costs for the carers of this type, which is a sign of instability. In most cases, the carer was a daughter who cared for her mother and shouldered a large share of care. This finding highlights sex and gender inequalities in informal caring and the need to share care work more equally to relieve caring daughters [55].
Compared to the two child-centred types, both spouse-centred types seem to be more stable. The rate of institutionalisation over one year in the type ‘spouse-centred earlier’ type was very low (5.56%). In the ‘spouse-centred later’ type, the rate of institutionalisation was the second lowest (15.69%). Compared to the ‘child-centred later’ type, the informal carers of the ‘spouse-centred later’ type experienced fewer role conflicts, although the care dependency and functional/cognitive impairment of the persons with dementia was the highest of all types, and almost all care arrangements of this type had been in place for longer than two years. Almost all carers of both spouse-centred types lived together with the person with dementia. Spouses often have high motivation to care for their partner [56]. Living in the same household and not being employed enables continuous company for persons with dementia. However, the often high emotional intimacy and reciprocity of a long-lasting relationship that can be lost during the progression of dementia may also affect spouses to a greater extent than other carers [57]. Having an informal carer who is present for most of the day and highly motivated to care seems to be the reason for the higher stability of spouse-centred care arrangements. Simultaneously, spouse carers tend to integrate other informal and formal carers less often into the care arrangements than child carers do. If a spouse cares for her or his relative mostly alone but is not able to care any longer (e.g., because of his or her own health problems), the stability of these care arrangements is endangered [58]. Early access to formal and informal support might be crucial for spouse-centred care arrangements to keep them stable.
In sum, our results highlight the heterogeneity of home-based care arrangements and underline the importance of recognising and understanding the different and changing needs of persons with dementia and their informal carers during the dementia and care trajectory. In general, spouse-centred care arrangements seem to be more stable than child-centred care arrangements.
Our study is not the first to look for subgroups or types of care arrangements for persons living with dementia. Wiegelmann and colleagues [59] constructed six different classes of care arrangements for persons living with dementia. Similar to our results, the structure of the dyadic relationship was an important distinguishing criterion in their study. In contrast to our results, Wiegelmann et al. identified one class in which the majority of the carers was neither a spouse nor an adult child of the person with dementia. In our results, these care arrangements shared many characteristics with adult–child carers and therefore did not form a separate type in our model. Furthermore, Wiegelmann et al. identified the age and sex of the carer as distinguishing criteria of care arrangements with a spouse as the carer. Although the sex of the carer could influence the experience of carers [17, 60], in our model, it did not correspond strongly with other included variables (see Additional file 1: Appendix C) and therefore did not lead to a separate type.
Janssen and colleagues constructed five different profiles of carers of persons with dementia [61]. They argue that it might be possible to categorise carers of persons with dementia along two axes. The first axis includes the age of the carer, the kinship relation between the carer and the person with dementia and the severity of dementia. The combination of aspects of the dyadic relationship with the progression of dementia into one axis of differences is not supported by our results as both aspects are related to different axes in our model. Their second axis includes the tendency towards stress and difficulties in adapting to stress. We did not include variables to measure the ability of the carer to adapt to stress. Therefore, we were unable to differentiate care arrangements along a corresponding axis. In the SoCA-Dem theory [15], the ability to adapt is part of the concept of ‘resources’ and influences the stability of home-based care arrangements. Therefore, it would be worthwhile to include appropriate variables in future research. Nevertheless, the adaptability of the carer is only one of many elements that influences the stability of home-based care arrangements [62].
Overall, the studies of Wiegelmann et al. and Janssen et al. as well as our study highlight that care arrangements for persons living with dementia are heterogeneous. The structure of the dyadic relationship is one important distinguishing criterion of home-based care arrangements identified in all studies.
Strengths and limitations
The SoCA-Dem theory is a suitable framework to guide the selection of relevant variables to construct different types of care arrangements. Our use of the SoCA-Dem theory as a theoretical framework is a major strength of the present study because it justifies the selection of variables. However, since our study is a secondary analysis, we were unable to include variables for all concepts of the entire SoCA-Dem theory. This could also be one reason for the high percentage of variance within the types. In future research, the concepts of the SoCA-Dem theory need to be operationalized. For instance, we were not able to include the ability of the informal carer to adapt and cope with stress (included in the concept ‘resources’ of the SOA-Dem theory), the quality of the relationship between the person with dementia and the informal carer (included in the concept ‘dyadic relationship’ of the SoCA-Dem theory), or the motivation of the informal carer to assume the carer role (included in the concept ‘carer role’ of the SoCA-Dem theory).
Our analytical approach – multiple correspondence analysis in combination with hierarchical cluster analysis – has the strength of a visual representation of the results, which enables a detailed interpretation of the structure of the data. However, the MCA requires categorical data with preferably only a few categories. Therefore, we transformed some continuous variables and many variables with more than two answer categories into variables with predominantly two answer categories. This transformation implies a reduction of information that may have shaped our results. In particular, the axis ‘dementia and care trajectory’ is formed by variables that are based on variables that initially have many answer categories or even a continuous level of measurement. Our four types of care arrangements are positioned along this axis. The clear border between the four types in relation to the ‘dementia and care trajectory’ might be influenced by our transformation of the data and might partly conceal the more continuous character of the dementia and care trajectory. However, intensification into a few categories and the accompanying reduction in complexity could be seen as aligned with the principle of parsimony, which helps to understand the underlying structures [63].
A final limitation is related to the representativeness of our sample and the generalizability of our results. The sample of the DemNet-D study was a convenience sample. To be included in the DemNet-D study, a care arrangement already had to be supported by a dementia care network and, hence, by the formal care system. Care arrangements at the very beginning of the dementia and care trajectory or without support from formal care providers might have been underrepresented in the DemNet-D study. Nevertheless, Wolf-Ostermann and colleagues [18] argued that the sample of the DemNet-D study is a valid representation of home-based care arrangements in Germany. Our study is a secondary analysis of the DemNet-D study, and our sample does not differ greatly from the entire DemNet-D sample. In comparison to the representative sample of the MUG-III study [64], in our sample, more men living with dementia and spousal carers were included. For a detailed comparison between our sample, the DemNet-D sample and the MUG-III study, see Additional file 1: Appendix F. The generalizability of our results is limited. It is possible that care arrangements at the beginning of showing dementia symptom or diagnose and at the beginning of the care trajectory and/or without contact to the formal health care system could form other types of care arrangements. Furthermore, the size of the types need to be interpreted with caution as spousal carers might be overrepresented in our sample. Finally, the study was conducted in Germany with its specific health care system, demography and social norms. It is possible that in other health care systems or countries the size of the types differs from our results or other types could be constructed.
Implications for research and practice
In research, persons with dementia and their informal carers are often constructed as a homogenous group with a unifying problem: dementia [5]. This conceptualisation neglects to recognise the heterogeneity of home-based care arrangements and could be one reason for the rather moderate evidence of effective interventions [8]. In response to this gap in the research, the effects of interventions are increasingly studied in subgroups divided, for instance, by gender, family relationship, ethnicity or dementia severity [6]. Our types have the advantage of simultaneously capturing several dimensions of differences and commonalities and thus point to possible interactions between important variables that are associated with the stability of care arrangements. Therefore, our results could be used to study the effects of interventions for different types of care arrangements.
However, interventions are predominantly not tailored to the needs of specific subgroups [65]. In the future, the effects of interventions should not only be studied for different types of care arrangements but interventions should also be specifically tailored to the different needs of these types of persons. Although our four types cannot capture the complexity of the individual situation of a specific care arrangement [42], they can help to guide the development of tailored interventions by better explaining and distinguishing care arrangements. However, this will not supersede the need for individual assessments of the needs of the involved persons [66] to tailor interventions and to deliver person-centred care [67].
