Clinical factors associated with death in 3044 COVID-19 patients managed in internal medicine wards in Italy: results from the SIMI-COVID-19 study of the Italian Society of Internal Medicine (SIMI)

Abstract

During the COVID-19 2020 outbreak, a large body of data has been provided on general management and outcomes of hospitalized COVID-19 patients. Yet, relatively little is known on characteristics and outcome of patients managed in Internal Medicine Units (IMU). To address this gap, the Italian Society of Internal Medicine has conducted a nationwide cohort multicentre study on death outcome in adult COVID-19 patients admitted and managed in IMU. This study assessed 3044 COVID-19 patients at 41 referral hospitals across Italy from February 3rd to May 8th 2020. Demographics, comorbidities, organ dysfunction, treatment, and outcomes including death were assessed. During the study period, 697 patients (22.9%) were transferred to intensive care units, and 351 died in IMU (death rate 14.9%). At admission, factors independently associated with in-hospital mortality were age (OR 2.46, p = 0.000), productive cough (OR 2.04, p = 0.000), pre-existing chronic heart failure (OR 1.58, p = 0.017) and chronic obstructive pulmonary disease (OR 1.17, p = 0.048), the number of comorbidities (OR 1.34, p = 0.000) and polypharmacy (OR 1.20, p = 0.000). Of note, up to 40% of elderly patients did not report fever at admission. Decreasing PaO₂/FiO₂ ratio at admission was strongly inversely associated with survival. The use of conventional oxygen supplementation increased with the number of pre-existing comorbidities, but it did not associate with better survival in patients with PaO₂/FiO₂ ratio < 100. The latter, significantly benefited by the early use of non-invasive mechanical ventilation. Our study identified PaO₂/FiO₂ ratio at admission and comorbidity as the main alert signs to inform clinical decisions and resource allocation in non-critically ill COVID-19 patients admitted to IMU.

Keywords: Comorbidity; Internal medicine; Mortality from COVID-19; Polypharmacy; SARS-CoV-2.

Fig. 1

Panel a shows the distribution of male (gray columns) and female (white columns) patients admitted to IMU and of deceased patients (black framed columns) by age decades. The distribution of deceased (black columns) and surviving (gray columns) patients stratified by number of comorbidities or chronic drugs is shown in panel b and c, respectively (the percentages above the black columns refer to the mortality rate). Panel d shows the distribution of deceased (black columns) and surviving (gray columns) patients by P/F class at admission

Fig. 2

The distribution of admitted patients over time (weeks) is stratified according to P/F classes and the mortality rate. The severity of respiratory impairment is represented in grayscale from light (white columns) to severe (black columns) P/F class. The red columns show the number of deceased patients (the numbers above the columns refers to the mortality rate)

Fig. 3

The percentage of patients treated by conventional oxygen supplementation (gray columns) and non-invasive mechanical ventilation (black columns) stratified by age decades (panel a) or number of comorbidities (panel b) is shown