COVID-19(8) frailty(6) COVID-19 infection(4) SARS-COV-2 infection(4) ICU(4) Older(4) age(3) SARS-CoV-2(3) Prognosis(3) COVID-19 research(2) intensive care unit(2) Laboratory(2) Ministry of Health(2) Dyspnea(2) conducted(2) Comprehensive(2) eight(2) Patient(2) prognostic(2) CIs(2) epidemiological(2) association(2) prospective observational cohort(2) Evidence(2) Multidimensional prognostic index(2) Stratification(2) Clinical characteristics(2) risk of death(2) not significant(2) multivariable analysis(2)