Association between Clinical Frailty Scale (CFS) and clinical presentation and outcomes in older inpatients with COVID-19

BACKGROUND: Frailty is a physiological condition characterized by a decreased reserve to stressors. In patients with COVID-19, frailty is a risk factor for in-hospital mortality. The aim of this study was to assess the relationship between clinical presentation, analytical and radiological parameters at admission, and clinical outcomes according to frailty, as defined by the Clinical Frailty Scale (CFS), in old people hospitalized with COVID-19. MATERIALS AND METHODS: This retrospective cohort study included people aged 65 years and older and admitted with community-acquired COVID-19 from 3 March 2020 to 31 April 2021. Patients were categorized using the CFS. Primary outcomes were symptoms of COVID-19 prior to admission, mortality, readmission, admission in intensive care unit (ICU), and need for invasive mechanical ventilation. Analysis of clinical symptoms, clinical outcomes, and CFS was performed using multivariable logistic regression, and results were expressed as odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: Of the 785 included patients, 326 (41.5%, 95% CI 38.1%–45.0%) were defined as frail (CFS ≥ 5 points): 208 (26.5%, 95% CI 23.5%–29.7%) presented mild-moderate frailty (CFS 5–6 points) and 118 (15.0%, 95% CI 12.7%–17.7%), severe frailty (7–9 points). After adjusting for epidemiological variables (age, gender, residence in a nursing home, and Charlson comorbidity index), frail patients were significantly less likely to present dry cough (OR 0.58, 95% CI 0.40–0.83), myalgia-arthralgia (OR 0.46, 95% CI 0.29–0.75), and anosmia-dysgeusia (OR 0.46, 95% CI 0.23-0.94). Confusion was more common in severely frail patients (OR 3.14; 95% CI 1.64-5.97). After adjusting for epidemiological variables, the risk of in-hospital mortality was higher in frail patients (OR 2.79, 95% CI 1.79-4.25), including both those with mild-moderate frailty (OR 1.98, 95% CI 1.23-3.19) and severe frailty (OR 5.44, 95% CI 3.14-9.42). Readmission was higher in frail patients (OR 2.11, 95% CI 1.07–4.16), but only in mild-moderate frailty (OR 2.35, 95% CI 1.17–4.75).. CONCLUSION: Frail patients presented atypical symptoms (less dry cough, myalgia-arthralgia, and anosmia-dysgeusia, and more confusion). Frailty was an independent predictor for death, regardless of severity, and mild-moderate frailty was associated with readmission. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12877-022-03642-y.