Health and service use in old age: longitudinal population based studies in Taiwan

In ageing societies such as that of Taiwan, the proportion of the population aged 65 years and older is growing faster than younger cohorts. The health and quality of life of elderly Taiwanese are therefore of increasing importance. The proportion of the population with poor health status increases with age, so the elderly are disproportionately higher users of health care services. Hence, it is becoming urgent to study the elderly population, with a focus on health status changes, the shortage of relevant health care services, and the consequential social impact. Little is known about the trends in, and the determinants of, health status and service use over time among community-living elderly population. Significant knowledge gaps exist with regard to the interrelationship between changes in health status and health care services use. The absence of substantial longitudinal studies in this field provides an opportunity for focused research on an elderly cohort over a period of ten years. The main purpose of this study was to assess health status change and its interrelationship with health care service use during the ageing process. A subsidiary goal of the study was to supplement this knowledge, to broaden the knowledge base of gerontological research and to inform the development of public policy related to medical care, health insurance and social welfare for the elderly. This study adopted a prospective design, with a multidimensional perspective using a closed cohort. Longitudinal data in a large random sample of community-based Taiwanese elderly were available for the period 1994-2004. Data collection commenced with an initial baseline survey in 1994, when the 1260 participants were 65 years old and over, with biennial follow-up of participants to 2004. There was continual surveillance of health status, service use and mortality between 1994 and 2004. This study was based on data collected using the Chinese-version of the Multidimensional Functional Assessment Questionnaire (CMFAQ). Health status, health care service use and their association were investigated cross-sectionally and longitudinally. Cross-sectional analyses of the patterns of health status and health care service use were conducted. These were complemented by longitudinal analyses on the time trends in, and determinants of, health status and health care service use. Development pathways (direct effect, lag effect and cross-lag effect) for chronic disease, disability and depression were investigated, and relationships between service use and change of health status were examined. After reviewing the causes of attrition (mainly death) and demonstrating that other loss to follow-up was unlikely to be a major source of bias, the overall data set was investigated, and the prevalence and other characteristics of health status (chronic disease, disability and depression) over the six waves of the study were summarized. This cross-sectional focus was then extended through a longitudinal analysis by examining the time trends in, and the determinants of, health status. Supplementing the cross-sectional and longitudinal analyses with path analysis to highlight the key pathways and associations between chronic disease, disability and depression. With a focus on the determinants of service use, Andersen’s behavioral model (Andersen & Newman, 1973) was used to identify how health status predicted service use. Finally, the major themes of the study were linked through investigating the pathways of disability and depression over time, as well as their relationship with health status and social service use. Through demonstrating the overall deterioration over time of health (chronic disease, disability and depression), the study identified the risk groups which should be targeted for new health interventions. A key group identified as being at risk was elderly women from low socio-economic status (SES), who were unmarried and did not exercise regularly. This study confirmed that reciprocal relationships exist among chronic disease, disability and depression. In particular, disability was the most powerful predictor of depression, while depression was the strongest predictor of the development of chronic diseases. Overall, chronic disease and depression jointly influenced the level of disability. The interactions and associated feedback loops confirm the notion that health decline seldom involves only a single body system. The study strongly supports the view that health status of the elderly is a dominant need indicator and predictor of use of health care services. Chronic disease results in greater use of medical services, while disability and depression result in greater use of social services. This lends credence to the proposition that disability and depression are of central importance to the future provision of health care services that will meet the long-term care needs of elderly people. This study has also contributed significantly to filling some knowledge gaps regarding the effects of social service use on health status and changes in that status. In particular, it was found that higher use of social services was associated with increased disability and depression. In the light of the continued ageing of the population, this study clearly indicates the need for devoting increased resources, in the form of medical and community services, to elderly people with chronic disease, disability and/or depression. Given the increasing importance of health problems and service use in the aged, it is important to gain a better understanding of these factors and their interrelationships in order to better allocate and sustain resources which would ultimately help to improve their health, well-being and quality of life. Keywords Chronic Disease, Disability, Depression, Service Use, CMFAQ, Community-living, Elderl