Assessing the association between frailty and outcome of COVID-19 infection

Principal Investigators: McGeer Allison J, Andrew, Melissa K, Simor, Andrew E: Sinai Health System (Toronto)

A novel coronavirus, SARS-CoV-2, emerged in December 2019 in Wuhan, China. This new virus causes a respiratory illness known as COVID-19, and is now the cause of a severe pandemic. Rapid transmission of this virus is fuelled by a high reproductive number, the substantial number of mild illnesses, and transmission which occurs prior to onset of symptoms or from patients with mild disease.
Although many cases of COVID-19 are mild, nearly one-fifth of infected patients experience severe or critical illness; the infection appears to have an overall case fatality rate of 2-3% and up to 7% of patients require intensive care unit admission. Strikingly, very few children develop illness. Adults across all age-categories may develop severe illness, but older adults are clearly disproportionately affected. In the largest case series to date from China case fatality rising drastically from 0.2% for individuals < 40 years of age to 14.8% for those ≥ 80.

Since that publication, it has become evident that the frail elderly appear to be even more affected than others: almost half of Canadian deaths to date have occurred in residents of long term care homes, and the case fatality rate in residents the first described outbreak in a long term care home was 30% (this is actually an underestimate because the manuscript was written and published while the outbreak was on-going).

Because many patients survive hospitalization without specific antiviral therapy, considerable effort has been expended to identify risk factors for severe outcomes because these would permit decisions about who should receive specific therapy once a therapy is identified, and because stratification by such variables would improve the implementation and interpretation of clinical trial data. To date, however, factors identified have not been highly predictive (e.g. male gender, smoking) or relatively uncommon (e.g. morbid obesity).

None of the studies to date, however, have considered whether frailty might be an important predictor of outcome. Frailty is defined as a medical condition of reduced function and health in older individuals. In many sub-populations, it is more strongly predictive of health outcomes than age. Frailty may also be associated with significant declines in immunity, which may impair the ability to respond to COVID-19. Frailty is thus an important candidate measure to consider studies of COVID19.

We propose an analysis leveraging an already created prospective cohort of COVID-19 infections, with the overall goal of identifying the extent to which frailty predicts outcomes of COVID-19 infections, and whether it should be considered – and is feasible to consider – as an inclusion criterion or a stratification variable in trials of therapeutics for this new infection.