This study confirmed the correlation between multimorbidity and self-rated health in home-based long-term care residents: residents with multimorbidity were more likely to report low self-rated health. In addition to a direct association between multimorbidity and self-rated health, there was an indirect effect of multimorbidity on self-rated health through three potential pathways: via depression, via health service use, and via depression and health service use.
The results showed that 59.4% of home-based long-term care residents had multimorbidity, which is lower than the percentage of older people with multimorbidity in a previous longitudinal nationwide survey in China. However, the difference may be a result of regional and participant differences. The mean self-rated health score in this study was 1.97, indicating that the health of home-based long-term care residents is poor. This result is the same as that of a previous study of long-term care residents in China. We also found that 67.7% of home-based long-term care residents had depression, higher than in a previous study conducted with Chinese older adults. This difference may reflect the poor physical condition of long-term care residents.
To our knowledge, this is the first population-based study of Chinese home-based long-term care residents to investigate the relationship between multimorbidity and self-rated health and the mediating role of health service use and depression. Previous studies have identified a correlation between multimorbidity and low self-rated health[17–19]. However, these studies have used different types of participants (e.g., older people in the community or in health facilities) or analytical methods (e.g., traditional regressions and correlations). Furthermore, the chronic diseases these studies focused on are frequently occurring diseases in the region. Although these studies differ in specific details, their findings regarding the negative effect of multimorbidity on self-evaluated health are consistent, and are supported by the present findings.
We found that multimorbidity was associated with an increased likelihood of depression in home-based long-term care residents. One study conducted with community-dwelling elderly people in eastern China indicated that people with multimorbidity were more likely to have depressive symptoms (odds ratio = 1.42; 95% CI = 1.19 to 1.70). Previous research has suggested that some chronic diseases like diabetes, stroke, and thyroid disorders cause or contribute to depression by causing pathophysiological changes in the brain, endocrine system, or immune system[36, 37]. Our finding of a correlation between depression and self-rated health supports previous survey evidence of this association in African American men. A study conducted in older people living in Shanghai found that both chronic disease and depression are predictors of self-rated health, and concluded that some depressive symptoms and depression-related negative emotions may lead elderly people to perceive their health negatively, thereby reducing their health satisfaction. These are possible explanations of our finding that depression mediates the association between multimorbidity and self-rated health. Some chronic diseases cause depression through pathophysiological changes, and multimorbidity aggravates depression symptoms (worse depression is associated with lower self-rated health).
We found that home-based long-term care residents with multimorbidity use health services more frequently, which has not previously been confirmed for long-term care residents, although previous studies on retired Chinese participants and Canadian home care clients with dementia have found such an association. Multimorbidity is associated with a wide range of disabilities and functional decline, which increase the demand for medical services. Unlike long-term health facility residents who have professional caregivers available 24 hours a day, people receive home-based long-term care services at a fixed time. This may explain the association between multimorbidity and health service use in home-based long-term care residents. This study showed an association between health service use and self-rated health, which reflects previous findings from Singapore. Frequent health service use is often a result of poor health status, which is also the main reason for low self-rated health. In addition, health service use was also associated with depression in this study, indicating that depression may predict health service use to some extent. In a study on American older adults, depressive symptoms were positively related to health service use, which is consistent with our results. A possible reason for this association is that depressive symptoms lead older people to have a negative perception of their health, thereby increasing their use of health services. We found a mediating role of health service use and a multiserial mediation pathway by which depression and health service use affect the association between multimorbidity and self-rated health. These mediation pathways have been discussed in previous research[18, 25]. Multimorbidity may cause disability, functional decline, and depression and may increase the demand for medical services. Frequent health service use may lead elderly people to perceive their health negatively, thus reducing their self-rating of health.
There were several study limitations. First, there was a higher proportion of females (58.8%) than of males. This may be because individuals covered by LTCI are older; in this study, the mean age of participants was 82.33 years. Second, a small number of participants with consciousness deficits were excluded, resulting in a slight decline in the efficiency of the questionnaire. Finally, the findings cannot be generalized to elderly people in long-term care facilities, and therefore cannot be used to provide guidance on improving the quality of life of elderly people in long-term care. These limitations need to be addressed in future research.