Comparing associations between frailty and mortality in hospitalised older adults with or without COVID-19 infection: a retrospective observational study using electronic health records

Background

The aim of this study was to describe outcomes in hospitalised older people with different levels of frailty and COVID-19 infection.

Methods

We undertook a single centre, retrospective cohort study examining COVID-19 related mortality using Electronic Health Records, for older people (65 and over) with frailty, hospitalised with or without COVID-19 infection. Baseline covariates included demographics, Early Warning Scores, Charlson Comorbidity Indices and frailty (Clinical Frailty Scale, CFS), linked to COVID-19 status.

Findings

We analysed outcomes on 1,071 patients with COVID-19 test results; 285 (27%) were positive for COVID-19.)The mean age at ED arrival was 79.7 and 49.4% were female. All-cause mortality (by 30 days) rose from 9% (not frail) through to 33% (severely frail) in the COVID negative cohort but was around 60% for all frailty categories in the COVID positive cohort. In adjusted analyses, the hazard ratio for death in those with COVID-19 compared to those without COVID-19 was 7.3, 95% CI: 3.00, 18.0) with age, comorbidities and illness severity making small additional contributions.

Interpretation

In this study frailty, measured using the Clinical Frailty Scale, appeared to make little incremental contribution to the hazard of dying in older people hospitalised with COVID-19 infection; illness severity and comorbidity had a modest association with the overall adjusted hazard of death, whereas confirmed COVID-19 infection dominated, with a seven-fold hazard for death.