The current study showed that predisposing (age), enabling (partnership status), and need factors (functional and cognitive impairment) predicted the use of outpatient, day and/or private nursing care of very old adults in NRW. Several predisposing (age, SES, community size), enabling (presence of children, partnership status, social isolation, loneliness) as well as need factors (functional and cognitive impairment, physical frailty, multimorbidity) were significantly associated with inpNCU.
Consistent with previous literature, the predisposing factor increasing age was associated with both odpNCU (cf. 7, 9, 13) and inpNCU (cf. 4, 8, 9, 12). This result underlines that nursing care needs increase with age. In the present study, very old adults with higher SES had lower likelihood of inpNCU, opposite to finding of Yu et al. (7) and Steinbeisser et al. (3). Since the majority of previous studies considering education level as indicator of social class found no relationship with inpNCU (3, 4, 7), this finding may indicate that use of the last occupation before retirement (22) could be more appropriate indicator of social status than educational level. Other explanation of these inconsistencies might be related to the higher age of the study participants, suggesting increase of socioeconomic gradient in health over time (cf. 31, 32). There is evidence that persons with higher SES experience better health status over the lifespan (31–33), which might result in lower likelihood of NCU (cf. 34). Furthermore, inconsistent with a study conducted in the US (12), there was lower likelihood of inpNCU among very old adults living in communities of NRW with less than 50,000 inhabitants. Taking the findings of Kuppler and Wagner (35) into account, lower inpNCU in smaller communities might be attributed to lower inpatient nursing care supply in these areas of NRW. Other perspective provides the study of Zimmermann et al. (24) reporting lower likelihood of physical frailty among very old adults who lived in small communities of NRW, which could lead to lower demand for inpNCU.
Looking at enabling factors, similar to previous findings, having children (cf. 12, 14) decreased the likelihood of inpNCU. Likewise, being in partnership reduced the demand of odpNCU (cf. 7, 9, 13) and of inpNCU (cf. 4, 8, 12). Moreover, social isolation and feeling lonely increased the likelihood of inpNCU, which is also in accordance with research literature (3, 4, 8, 9). On the one hand, these findings may indicate that the lack of close social connections (such as absence of children or partner) and loneliness may facilitate the use of inpatient nursing care services. On the other hand, admission to long-term care facilities might lead to the loss of existing social networks and consequently to loneliness (cf. 36).
The majority of individual need characteristics played an important role in explaining of NCU of very old population. In line with previous research, participants with higher impairment in ADL and IADL had increased likelihood of odpNCU (cf. 9–11) and of inpNCU (cf. 3, 4, 9, 12). Similarly, lower cognitive function was associated with increased demand for both odpNCU and inpNCU (4, 8, 9, 11). In contrast to previous studies (3, 5, 9, 37), experiencing physical pre-frailty and frailty as well as multimorbidity was lower in inpNCU than in noNCU. Protective effect of inpNCU on multimorbidity and physical frailty might be explained according to Andersen (6) in terms of effective access to inpatient nursing care services in NRW, when the use of the services contributes to an improvement of physical health status. However, this effect could be also related to a bias of the analysis sample, since proxy interviews were excluded.
The present study investigated for the first time the relationship between individual characteristics and the different types of NCU using representative data for the very old population in NRW. For the definition of NCU, self-reported information as well as information from interviewers were considered to identify NCU status as accurately as possible. Furthermore, besides sociodemographic and health characteristics included in previous German studies (3–5), social predictors of NCU (such as isolation or loneliness) were included. However, the study has also some limitations. First, for the definition of physical frailty, four instead of five criteria recommended by Fried et al. (30) were used, because walking speed was not assessed in NRW80+. The exclusion of this criterion was previously found to have the smallest impact on predicting adverse health outcomes (38). Second, the proxy interviews had to be excluded from the analyses because of the absent measurement of handgrip strength of the target person. Multiple imputation was performed to replace the missing values in order to minimize possible bias. Third, since cross-sectional data were used for the analysis, no conclusions about causal relationships can be derived.
Applying Andersen's behavioral model (6), the dominance of individual need factors in explaining of odpNCU suggests that very old adults in NRW have an equitable access to this kind of nursing services based on actual care demands. Instead, the access to inpNCU could be characterized as inequitable because social structure, region, and enabling resources determine who receives the care (cf. 6). However, the findings suggest that inpNCU of very old adults might serve as a compensation of missing social resources (i.e., closest relatives as potential informal caregivers). Additionally, the results indicate that prevention of social isolation and loneliness, recognized as indicators of social frailty (15, 18), has not been sufficiently established in residential care facilities in NRW. Since the evidence show that social frailty predict physical frailty, disability, and mortality (39–42), appropriate interventions to enhance social inclusion of very old adults living in inpatient nursing care settings are needed. Finally, there might be an indication of inequitable supply of institutional care services in smaller communities of NRW. Further research is needed to investigate this aspect in more detail.