Fragilidade física e multidimensional no idoso brasileiro: comparação, efeito mediador dos recursos sociais e eventos adversos - Estudo FIBRA - BR

Abstract

The accelerated aging of the population, especially in developing countries such as Brazil, has shown the need to understand the vulnerability and frailty of older adults. Frailty is geriatric condition is defined as a clinical syndrome of multifactorial character, characterized by reduced physiological reserve and reduced resistance to stressors resulting from age-related cumulative decline in several organ systems, mainly the immune, endocrine, musculoskeletal, and nervous systems. The physiological system decline leads to loss of homeostatic capacity and greater vulnerability to adverse outcomes, including falls, hospitalization, functional disability, institutionalization, and death. The approach frailty from a multidimensional perspective, the understanding the relationship between frailty and functional disability and the longitudinal follow-up of older adults at different stages of frailty can broaden the search for more specific indicators of aging and motivate new lines of research. In this context, the objective of this thesis was to analyze frailty from a multidimensional perspective and the impact of physical frailty on functional disability and mortality in Brazilian older adults after 10 years. Study 1 specifically aimed to construct a three-dimensional model to assess frailty in Brazilian older adults based on the Tilburg Frailty Indicator and the variables available in the FIBRA-BR Study and compare the dimensions of the model created with the categories of the physical frailty phenotype. This was a cross-sectional study that analyzed data from the FIBRA survey (2008–2009). The variables available in the FIBRA-BR comprised the multidimensional model (physical, social, and psychological dimensions) and were considered the categories of the physical frailty phenotype. First, Pearson’s chi-square test was used to analyze the associations between each variable of the multidimensional frailty model and the physical phenotype categories. Factorial analysis through the principal component method and varimax rotation were used to analyze the multidimensional frailty model to determine the composition of the physical, social and psychological dimensions. The two models were compared using ANOVA with post hoc Tukey’s test. Study 1’s results showed that the models of physical and multidimensional frailty are complementary and provide relevant information from the social and psychological domains for the care of the elderly in different stages of frailty. Study 2 aimed to test the mediating role of living alone and the personal network in the relationship between physical frailty and inability to perform BADL and IADL in elderly Brazilians. Thus, this is a cross-sectional study that used data from 3,569 elderly from the FIBRA Study collected in 2008–2009. The independent variable was the physical frailty phenotype categorized as vulnerable elderly (frail and pre-frail) and robust (non-frail). The dependent variables were ABVD and AIVD, evaluated using the Katz Index and Lawton and Brody scale, respectively. As mediating variables, personal networks (having someone who can help in case of need, visiting, and receiving visits) and self-report of living alone (yes or no) were considered. Linear regression models were used to analyze the mediator effect, estimated by the bootstrapping method, using the SOBEL procedure. This study’s results showed that social networks and living alone mediated the relationship between frailty and disability, reinforcing the importance of analyzing the social dimension of frail older adults. Thus, the strengthening of social networks, the neighborhood network and the family can favor social connections, increase social support, and maintain the functional independence of vulnerable elderly. Study 3 specifically aimed to evaluate a longitudinal association between physical frailty and incapacity to perform BADL and IADL and mortality in a subsample of community elderly from the FIBRA Study, Belo Horizonte. This longitudinal study analyzed 200 elderly from Belo Horizonte, evaluated in 2009 (time 1) and re-evaluated in 2019 (moment 2). Age, sex, self-reported medical diagnosis of depression, inability to perform basic and instrumental activities of daily living (ABVD and IADL), were assessed using the Katz Index and the Lawton and Brody Scale; the phenotypic criteria of physical frailty were obtained at moment 1. At moment 2, the BADL and IADL were reassessed and recording the deaths that occurred between 2009 and 2019. For analysis purposes, the frailty classification of the older adults was categorized into vulnerable (pre-frail and frail) and robust (not frail). The generalized estimation equation model and the Cox proportional-hazards model were used in the data analysis. The results of this study showed the physical frailty is longitudinally associated as adverse outcomes, disability, and death. These results may contribute to a broader look at vulnerable elderly and direct care strategies that can delay or prevent health problems arising from frailty.