The interplay of post-acute COVID-19 syndrome and aging: a biological, clinical and public health approach

Abstract

The post-acute COVID-19 syndrome (PACS) is characterized by the persistence of fluctuating symptoms over three months from the onset of the possible or confirmed COVID-19 acute phase. Current data suggests that at least 10% of people with previously documented infection may develop PACS, and up to 50-80% of prevalence is reported among survivors after hospital discharge. This viewpoint will discuss various aspects of PACS, particularly in older adults, with a specific hypothesis to describe PACS as the expression of a modified aging trajectory induced by SARS CoV-2. This hypothesis will be argued from biological, clinical and public health view, addressing three main questions: (i) does SARS-CoV-2-induced alterations in aging trajectories play a role in PACS?; (ii) do people with PACS face immuno-metabolic derangements that lead to increased susceptibility to age-related diseases?; (iii) is it possible to restore the healthy aging trajectory followed by the individual before pre-COVID?. A particular focus will be given to the well-being of people with PACS that could be assessed by the intrinsic capacity model and support the definition of the healthy aging trajectory.

Fig. 1

conceptualizes an interaction model of frailty and resilience into four different phenotypes, namely “fit and resilient”, “fit and non-resilient”, “frail and resilient” and “frail and non-resilient” in comparison to a healthy aging trajectory. Fig. 1A shows the impact of COVID stress in initially fit individuals. The first scenario describes Fit and resilient people who are able to regain the pre-COVID health status in a relatively short period of time (Fig. 1A-2). The Fit and non-resilient phenotype represents the subset of individuals in which the acute COVID stress leads rapidly to disability with dramatic change in the initial optimal health condition (Fig. 1A-3). Fig. 1B shows the impact of COVID stress in initially frail individuals. The Frail and resilient phenotype comprises individuals who were frail before COVID onset, but with preserved resilience (Fig. 1B-4). The last scenario depicts frail and non-resilient phenotype, represents the most vulnerable individuals in which COVID stress makes them rapidly develop irreversible disability (Fig. 1B-5). Abbrevations: PACS – post acute COVID-19 syndrome.

Fig. 2

Modena PACS Clinic: Multidisciplinary and multidimensional assessment and health care model. Abbrevations: 6MWT – 6 min walking test; ASMI – appendicular skeleteal muscle index; DASS (questionnaire) – depression, anxiety and stress scale; EQ5D5L (questionnaire) – EuroQoL-5 dimension-5 level; NAFLD/MAFLD – non alcoholic fatty liver disease/metabolically associated fatty liver disease; PACS - post-acute COVID-19 syndrome; PROMs – patient-related outcome measures; SF-36 (questionnaire) – 36 item short form health survey; SPPB – short physical performance battery; VAT – visceral adipose tissue.