The multidimensional prognostic index (MPI) for the prognostic stratification of older inpatients with COVID-19: A multicenter prospective observational cohort study

Background: The topic of prognosis in COVID-19 research may be important in adopting appropriate clinical decisions. Multidimensional prognostic index (MPI) is a frailty assessment tool widely used for stratifying prognosis in older people, but data regarding inpatients, affected by COVID-19, are not available. Objectives: To evaluate whether MPI can predict in-hospital mortality and the admission to intensive care unit (ICU) in older inpatients hospitalized for COVID-19 infection. Methods: In this longitudinal, Italian, multi-center study, older patients with COVID-19 were included. MPI was calculated using eight different domains typical of comprehensive geriatric assessment and categorized in three groups (MPI 1 ≤ 0.33, MPI 2 0.34–0.66, MPI 3 > 0.66). A multivariable Cox's regression analysis was used reporting the results as hazard ratios (HRs) with 95% confidence intervals (CIs). Results: 227 older patients hospitalized for SARS-CoV-2 infection were enrolled (mean age: 80.5 years, 59% females). Inpatients in the MPI 3 were subjected less frequently than those in the MPI 1 to non-invasive ventilation (NIV). In the multivariable analysis, people in MPI 3 experienced a higher risk of in hospital mortality (HR = 6.30, 95%CI: 1.44–27.61), compared to MPI 1. The accuracy of MPI in predicting in hospital mortality was good (Area Under the Curve (AUC) = 0.76, 95%CI: 0.68–0.83). People in MPI 3 experienced a significant longer length of stay (LOS) in hospital compared to other participants. No association between MPI and ICU admission was found. Conclusions: Frailty- as assessed by high MPI score - was associated with a significant higher risk of in-hospital mortality, longer LOS, and lower use NIV, whilst the association with ICU admission was not significant. These findings suggest that prognostic stratification by using the MPI could be useful in clinical decision making in older inpatients affected by COVID-19.