Beyond Chronological Age: Frailty and Multimorbidity Predict In-Hospital Mortality in Patients With Coronavirus Disease 2019

Abstract

Background: We evaluated whether frailty and multimorbidity predict in-hospital mortality in patients with COVID-19 beyond chronological age.

Method: A total of 165 patients admitted from March 8th to April 17th, 2020, with COVID-19 in an acute geriatric ward in Italy were included. Predisease frailty was assessed with the Clinical Frailty Scale (CFS). Multimorbidity was defined as the co-occurrence of ≥2 diseases in the same patient. The hazard ratio (HR) of in-hospital mortality as a function of CFS score and number of chronic diseases in the whole population and in those aged 70+ years were calculated.

Results: Among the 165 patients, 112 were discharged, 11 were transferred to intensive care units, and 42 died. Patients who died were older (81.0 vs 65.2 years, p < .001), more frequently multimorbid (97.6 vs 52.8%; p < .001), and more likely frail (37.5 vs 4.1%; p < .001). Less than 2.0% of patients without multimorbidity and frailty, 28% of those with multimorbidity only, and 75% of those with both multimorbidity and frailty died. Each unitary increment in the CFS was associated with a higher risk of in-hospital death in the whole sample (HR = 1.3; 95% CI = 1.05-1.62) and in patients aged 70+ years (HR = 1.29; 95% CI = 1.04-1.62), whereas the number of chronic diseases was not significantly associated with higher risk of death. The CFS addition to age and sex increased mortality prediction by 9.4% in those aged 70+ years.

Conclusions: Frailty identifies patients with COVID-19 at risk of in-hospital death independently of age. Multimorbidity contributes to prognosis because of the very low probability of death in its absence.

Keywords: COVID-19; Frailty; In-hospital mortality; Multimorbidity.

Figure 1.

Kaplan–Meier curve for survival by multimorbidity (MM) and frailty combinations and discharge rate (frailty without multimorbidity was absent).

Figure 2.

ROC curves for Clinical Frailty Scale (Fr) score and number of chronic conditions (MM) in the prediction of mortality. AUC and 95% confidence intervals (95% CIs) were estimated through bootstrapping (N = 2000). The table shows sensitivity (Sens.), specificity (Spec.), positive and negative predictive values (PPV and NPV), and positive and negative likelihood ratios (LLR+ and LLR−) for frailty (CFS ≥ 6) and multimorbidity (2+ chronic condition) in the prediction of mortality.