Transitions in Functional Status and Frailty Among Post-Hospitalized COVID-19 Oldest-Old Adults: An 18-Month Follow-Up Study

<b>Objectives</b>: This study seeks to analyze physical function and frailty transitions in older adults at 1, 12, and 18 months after hospital discharge for coronavirus disease (COVID-19). Furthermore, we examined risk factors associated with patterns of changes. <b>Methods</b>: This is an observational, longitudinal, unicentric study. Participants aged ≥80 years who were admitted to a Spanish tertiary hospital and survived COVID-19 were included. Functional status was evaluated at baseline and after 1, 12, and 18 months of discharge using the Barthel Index (BI) and Functional Ambulation Category (FAC), and frailty was assessed using the FRAIL scale. Clinical, sociodemographic, and functional parameters were evaluated as covariates. <b>Results</b>: Two hundred and thirty-three individuals (mean age 86.2 ± 4.0 years, 48.9% men) were included. Patterns of changes were classified into three categories as follows: no changes (i.e., same score at baseline and follow-up), improvement (i.e., better results at follow-up), and worsening (i.e., detriments at follow-up). Worse frailty status at baseline [relative risk ratio (RRR) = 1.39] and longer length of stay (RRR = 1.03) were associated with higher risk of frailty impairment (worsening pattern). Older age (RRR = 1.11), longer length of stay (RRR = 1.03), and worse baseline physical function (RRR = 1.01) and FRAIL scores (RRR = 1.37) were associated with impairments in physical status at 18 months. <b>Conclusions</b>: Three distinct patterns of changes in functionality and frailty were observed among older adults discharged after COVID-19. Age, length of stay, and worse frailty and functional status at baseline emerged as significant risk factors for worsening in the examined conditions.