RESUMEN
BACKGROUND: Older people hospitalized for COVID-19 are at highest risk of death. Frailty Assessment can detect heterogeneity in risk among people of the same chronological age. We investigated the association between frailty and in-hospital and medium-term mortality in middle-aged and older adults with COVID-19 during the first two pandemic waves. METHODS: This study is an observational multicenter study. We recorded sociodemographic factors (age, sex), smoking status, date of symptom onset, biological data, need for supplemental oxygen, comorbidities, cognitive and functional status, in-hospital mortality. We calculated a Frailty Index (FI) as the ratio between deficits presented and total deficits considered for each patient (theoretical range 0-1). We also assessed the Clinical Frailty Scale (CFS). Mortality at follow-up was ascertained from a regional registry. RESULTS: In total, 1344 patients were included; median age 68 years (Q1-Q3, 56-79); 857 (64%) were men. Median CFS score was 3 (Q1-Q3 2-5) and was lower in younger vs. older patients. Median FI was 0.06 (Q1-Q3 0.03-0.09) and increased with increasing age. Overall, 244 (18%) patients died in-hospital and 288 (22%) over a median follow-up of 253 days. FI and CFS were significantly associated with risk of death. In two different models using the same covariates, each increment of 0.1 in FI increased the overall hazard of death by 35% (HR=1.35, 95%CI 1.23-1.48), similar to the hazard for each increment of CFS (HR=1.37, 95%CI 1.25-1.50). CONCLUSIONS: Frailty, assessed with the FI or CFS, predicts in-hospital and medium-term mortality and may help estimate vulnerability in middle-aged and older COVID-19 patients.