Health-related quality of life of individuals sharing a household with persons with dementia

Little is known about health-related quality of life (HrQoL) in the social environment of persons with dementia (PWD), with the exception of caregivers. This article examined the HrQoL of individuals sharing a household with PWD, and compares it to those not living with PWD, using a representative survey of German households. Results revealed a reduced HrQoL among those sharing a household with PWD. The health status of the individual, and the total number of persons in the household, had a major impact on HrQoL. No difference was found in the HrQoL of those sharing a household with PWD, who were also the primary informal caregivers, and other persons in the household. Further research focusing on HrQoL in the social environment of PWD is needed.

Dementia is the most common mental illness in old age, with approximately 1.5 million people affected in Germany [1]. The prevalence is estimated to be 1.5% of persons aged 65 (n = 64,300) and 40% of persons aged 90 (n = 281,700) [1]. Due to demographic changes, the overall number of PWD is expected to increase in the coming decades, so that the number of PWD will double by the year 2050 to approximately 3.1 million [1].

In the early stages of the disease, dementia patients usually live at home, and care is often provided informally by relatives and friends [2‐4]. In particular, care is provided by persons who are married or partnered (60%), who have a higher level of education (37%) and who have no children (68%). The majority of informal caregivers (50%) are in full-time employment, whilst 43% are unemployed [5]. In more than 60% of these cases, informal care is provided by women [6]. In the later stages of the disease, cognitive and physical impairments worsen, so that half of patients require 35 h of care, or more, per week [7]. At this stage, professional care is needed [4, 8]. Furthermore, with increasing cognitive and physical impairments, HrQoL of PWD deteriorates [9]. In particular, HrQoL decreases when residential care is unavoidable and patients have to leave their familiar living environment [9].

Informal care demands are associated with physical strain and mental distress for primary informal caregivers [10]. As a significant amount of time is spent providing informal care, approximately 43% of the primary informal caregivers are not employed, particularly if care is being provided to individuals in later stages of dementia [11]. Due to negative consequences on everyday life, primary informal caregivers often suffer from mental illnesses, such as depression, anxiety or stress [12, 13], as well as a reduced HrQoL [10]. A recently published systematic review showed heterogeneous results among international studies on the HrQoL of primary informal caregivers for PWD [10]. Overall, socio-demographic characteristics, caregiver–patient relationship, dementia characteristics (duration of dementia, age of onset, functional impairment, comorbidities), demands of caring, caregiver health, caregiver emotional well-being, support received, caregiver independence, caregiver self-efficacy, and worrying about the future were found in 41 studies to be associated with HrQoL of persons primarily providing informal care. Only one study analyzed the HrQoL of primary informal caregivers in Germany [14].

Caring for PWD not only affects the HrQoL of those living with PWD, who are also the primary informal caregiver, but also that of other household members [12, 13]. Especially in the case of dementia, household members are faced with an additional burden with respect to care and supporting PWD in their everyday life. Furthermore, the person who acts as the primary informal caregiver often have to balance work, caregiving and their personal interests [15]. It seems reasonable, that similar to the primary informal caregiver, individuals who live with a PWD may also experience be physically strain and/or mental stress, which in turn would influence their HrQoL negatively. Although the severity of dementia varies from person to person, the relationship between PWD and family members and friends are likely to change over time due to changed communication (e.g. PWD forget names and words) and altered behavior (some PWD become more impatient or aggressive) [16]. These difficulties can place an additional burden on family members and friends. Even though existing household surveys [e.g. the German Socio-Economic Panel (SOEP)] provide data to assess the impact of dementia on household members, the HrQoL of those sharing a household with PWD, who are not primary informal caregivers has not been addressed in the literature. It is important to address this gap in order to identify the possible health impacts for those sharing a household with PWD.

Therefore, the aim of this study was to build on existing literature on the HrQoL of persons who are the primary caregivers for PWD, by including all household members of PWD. Based on the SOEP, the HrQoL of individuals sharing a household with PWD was compared with the HrQoL of persons not living with PWD (research question 1). In addition, determinants of HrQoL among those sharing a household with PWD were assessed (research question 2).

The current study included n = 213 individuals who share a household with PWD, of whom n = 60 (28%) were primary informal caregivers and n = 87 (n = 41%) were female. The mean age of individuals sharing a household with PWD was 57 years, whereas the mean age of persons not living with PWD (n = 66,218) was 47 years. Approximately 60% of those sharing a household with PWD were married, whereas 58% of persons not living with PWD were married and 28% were single. Thus, those sharing a household with PWD were older, more likely to be male, more likely to be widowed, had a higher number of diseases and lived with a lower number of persons within the household, compared with persons not living with PWD. Neither groups, however, differed with regard to their educational level. Among those sharing a household with PWD, the mean PCS score was 43.4, the mean MCS score was 46.4, and the mean SF-6D index scores was 0.66 in the year dementia was diagnosed. The mean PCS, MCS and SF-6D index scores of persons not living with PWD were 51.0, 49.8 and 0.74, respectively. The sociodemographic characteristics of the sample are shown in Tables 1 and 2.

In the mixed-effects models, those sharing a household with PWD had a significantly lower HrQoL compared with persons not living with PWD (Table 3). Among those sharing a household with PWD, a higher number of diseases was significantly associated with a difference in mean PCS, MCS, and SF-6D index scores of − 0.90 (p = 0.003), − 0.86 (p = 0.013), and − 0.01 (p < 0.001), respectively (Table 4). In addition, those sharing a household with PWD, who were also separated (n = 5) had lower MCS scores (− 11.46; p < 0.001) and lower SF-6D index scores (− 0.09; p = 0.005) compared to their married counterparts (n = 114). Individuals sharing a household with PWD, who graduated after 11 years in school (n = 5) had a significantly higher PCS score than those who’d not graduated (+ 6.92; p = 0.005; n = 25). PCS scores of those sharing a household with PWD, who lived in smaller households were significantly lower (− 5.99; p = 0.009), compared with those in larger households. Marital status, gender, age, and informal caregiving was not found to have a significant influence on the HrQoL of those sharing a household with PWD.

Subgroup analyses revealed significantly lower MCS and SF-6D index scores among those sharing a household with PWD, who were also primary informal caregivers, compared with persons not living with PWD, whilst the PCS scores did not significantly differ (Table 5). Furthermore, individuals sharing a household of PWD, who did not act as the primary informal caregiver, had significantly lower PCS, MCS and SF-6D index scores than persons not living with PWD (Table 6).

Based on data from a representative household survey, to our knowledge, this study was the first to show that all individuals who share a household with PWD had a reduced HrQoL, compared to persons not living with PWD. As comparable international studies on HrQoL in the home environment are not available, literature on HrQoL of primary informal caregivers will be discussed. The HrQoL of persons primarily providing informal care to PWD is known to be reduced compared with other persons in the household [10, 26]. In particular, primary informal caregivers of PWD had a higher burden of care and a lower HrQoL than primary informal caregivers of individuals not suffering from dementia [27]. A higher burden of care was associated with a lower HrQoL [28]. Behavioral problems and psychological symptoms in particular have been found to constitute a significant aspect of the burden of primary informal caregiving [29]. At the same time, taking on such a task is never without consequences for the social environment. In the current study, differences in HrQoL between those sharing a household with PWD, who act as the primary caregiver, and other persons in the household, were not observed. However, it is conceivable that, similar to persons who are the primary informal caregiver, behavioral problems and psychological symptoms of PWD may also act as a burden for other household members. In this context, living with PWD can be a challenge, irrespective of whether the individual is acting as the primary informal caregiver, as individual needs are often put on hold, which in turn, could have negative health consequences.

Factors that were negatively related to the HrQoL of those sharing a household with PWD in the current study were the number of diseases and the total number of persons in the household. This was expected, since multimorbidity compromises health and thereby HrQoL [10]. Furthermore, HrQoL was significantly lower in smaller households than in larger households. Most households consisted of one or two other adults in addition to PWD. There was a significant difference in the PCS score between households with 1–3 persons (mean PCS score of 38–39) and households with 4 or 5 persons (mean PCS score of 44–45). As the total number of persons in a household increased, the mean age of those persons decreased. In households with an individual in addition to the PWD, persons had a mean age of 78, whereas in households with 5 or more members, the mean age was 36. At the same time, in households with a member in addition to the PWD, 18% of the household members reported being single, whilst this was true for 48% of the persons in households with 5 or more members. Therefore, smaller households seemed more likely to consist of married or partnered persons, whereas larger households seemed more likely to be joint or multi-generation households. However, the differences in HrQoL that are associated with the number of persons in the households cannot be attributed to age and marital status alone. Drawing on findings from the literature, HrQoL of primary informal caregivers was found to be related to demographic factors, caregiver–patient relationship, dementia characteristics (duration of dementia, age of onset, functional impairment, comorbidities), caregiver demands, caregiver health, caregiver emotional well-being, support received, caregiver independence, caregiver self-efficacy, and concerns about the future [10]. Similar to persons who act as the primary informal caregiver to the PWD, the results of the current study determined that the health of those sharing a household with PWD was related to their HrQoL. However, other factors described in the literature, that may also be relevant to the HrQOL of other household members, were not surveyed in the SOEP. As relationships between household members are very different and the social structures in individual households vary, the way in which factors influence the HrQoL those living with PWD is not currently well understood. The association between these factors and HrQoL appears to be multifactorial, in that several factors may influence each other.

The HrQoL of those sharing a household with PWD was reduced compared with persons not living with PWD. In particular, those living with PWD in small households, and multi-morbid individuals sharing a household with PWD, had a lower HrQoL. No difference in HrQoL was observed between those sharing a household with PWD, who act as the primary caregiver, and other persons in the household. Further research focusing on the HrQoL in the social environment of PWD is needed. In particular, the association between the HrQoL of persons who act as the primary caregiver and other persons sharing a household with PWD should be investigated.