Background & aimThe COVID-19 pandemic has had a disproportionate impact upon older people; the frailty construct has been used to assess risk of poor outcomes in many settings. The aim of this systematic review was to quantify the association between frailty and COVID-19 in relation to mortality in hospitalised patients.MethodsMedline, Embase and the grey literature were searched for papers from inception to 10th September 2020. Screening (and grading) was undertaken by two reviewers according to pre-defined inclusion and exclusion criteria. Met-analysis was not possible so the result were summarised narratively.Results2276 papers were screened resulting in 16 being included in the review. All studies were from Europe, mostly the UK; the median sample size was 308.5, mean age of participants 78.7 and 42% were female. 15/16 used the Clinical Frailty Scale; reported mortality ranged from 19 to 65%. Most, but not all studies showed an association between increasing frailty and a greater risk of dying. Two studies indicated a sub-additive relationship between frailty, COVID-19 and death, and one study showed no increase in dying.ConclusionsThis review showed that whilst many studies have shown an association between an increased risk of COVID-19 related death with increasing frailty, other studies demonstrate a more nuanced understanding of frailty and outcomes in COVID-19 is needed. Clinicians should exert caution in placing too much emphasis on the influence of frailty alone when discussing likely prognosis in older people with COVID-19 infection.Key pointsFrailty is being used to assess the risk of dying from COVID-19Researchers should ensure that frailty scales are used as designed when planning and reporting future research.Emerging studies demonstrate a complex relationship between frailty and COVID-19 related deathsClinicians should exert caution in placing too much emphasis on the influence of frailty in older people with COVID-19