The complex relationship between frailty and daily functioning, and the influence of social participation and psychological resilience in the oldest old

Frailty, defined as a condition or syndrome resulting from a reduction in the reserve capacity of multiple systems to the extent that a number of physiological systems approach or pass the threshold of symptomatic clinical failure, should preferably be prevented and/or countered to promote healthy ageing. The syndrome leads to negative health outcomes such as hospitalisation, falls, disabilities and even early death. This is evitable since frailty and specifically the earlier stage, prefrailty, are reversible. However, to date, there is no consensus on the definition and the operationalisation of frailty, which is essential to recognise the predictors and protectors at an early stage. In particular, this thesis wanted to contribute to the gap in research about the complex relationship between frailty and activities of daily living (ADLs ), and additionally further investigate social participation and psychological resilience in community-dwelling octogenarians. It is clear from previous research that ADLs, social participation, and psychological resilience can potentially be used to prevent frailty, but many uncertainties still need to be explored. Firstly, a systematic review analysed (i) if, (ii) to what extent, and (iii) how ADLs (according to the typology of basic (b-), instrumental (i-), and advanced (a-)ADLs) are evaluated by frailty instruments. The study revealed that more than half of the frailty instruments contained ADL items. Those results indicated that both concepts (frailty and limitations in ADLs) appeared to be highly intertwined, without a clear distinction between the two. Due to the inclusion of ADL items in frailty instruments and the use of limitations in ADLs as a negative health outcome, the problems of circular reasoning, concerns regarding contamination, and invalid research results arose.
This PhD thesis was part of the extensive prospective longitudinal BUTTERFLY study aiming to identify the early predictors of (pre)frailty and the characteristics of healthy ageing in community-dwelling octogenarians. Two cross -sectional analyses were conducted aiming to evaluate (i) the interrelationship between daily functioning, social participation and prefrailty and (ii) whether psychological resilience could mediate the relationship between daily functioning and the frailty state in octogenarians. No associations were found for social participation and psychological resilience with prefrailty, though limitations in a-ADLs , the most complex ADLs, were associated factors of prefrailty. Next, a prospective longitudinal study probed to examine whether changes in b-, i -, a -ADLs, social participation, and psychological resilience between baseline and 6 months predicted a transition from robustness to (pre)frailty and vice versa among community-dwelling older individuals over a follow-up period of one year. Limitations in a-ADLs were found predictors of aworsened frailty transition. Therefore, the a-ADLs could be added to the processes that combine frailty stages and limitations in ADLs. It could be hypothesised that limitations in a-ADLs and i-ADLs may be predictors and characteristics, respectively, while limitations in b -ADLs can be regarded as negative consequences of frailty. Moreover, being a woman and social participation, specifically becoming a board member over a period of 6 months, were protectors of frailty and thus related to an improved frailty transition after one year. Finally, considering the impact of the COVID-19 pandemic on the lives of community dwelling older persons, the last study investigated (i) whether the lockdown had an impact on the quality of life (QoL), loneliness, negative feelings, and meaningful daily activities and (ii) if the (pre)frailty status played a role. The engagement in meaningful activities explained a decrease in QoL, together with the 1experience of emptiness in life, the use of medication, and the feeling of depression. Frailty did not contribute to the decreased QoL during the lockdown. Understanding which components contribute to and might affect a person’s QoL of the oldest old could be a fundamental issue showing that meaningful activities might be essential for a person’s QoL. Improving the understanding of this relationship between frailty and ADLs, early identification, the prevention of (pre)frailty and its negative health outcomes, could support policymakers in developing preventive policies and interventions to retain healthy ageing in the oldest old. From all this research, it is recommended to (i) choose a frailty instrument that does not include b-ADLs when investigating them as negative health outcome, and (ii) encouraging meaningful activities to promote healthy lifestyle behaviours in the oldest old to target frailty.