Ricerc@Sapienza

Dear Editor,
in the recent report of Munblit and coworkers [1], authors observed that the
combination of clinical features was sufficient to diagnose COVID-19 indicating that
laboratory testing is not critical in real-life clinical practice. To date, all patients admitted to
Emergency Department with acute respiratory failure and/or fever should be considered as a
suspected SARS-CoV-2 infection [2-3], and an early recognition of etiology and the prompt
therapeutic management are crucial to improve survival [4-5].
From March to July 2020, we performed a prospective, multicenter study
(RESILIENCY study). During the study period, all patients hospitalized for suspected or
confirmed COVID-19 were prospectively recruited in 3 large hospitals in Rome, Italy. All
patients with suspected SARS-CoV-2 infection, admitted to the hospital in case of fever
and/or hypoxemic respiratory failure (PaO2 <60 mmHg at rest in ambient air) or of
exacerbation of underlying diseases or severe symptoms not manageable outside the hospital,
were evaluated according to a predefined protocol (see Figure 1).
Overall, 653 patients were included in the study: 309 (47.3%) patients with confirmed
COVID-19 and 344 (52.7%) without COVID-19, hospitalized for other causes. Baseline
characteristics and outcomes of the study population showed that the main causes of
hospitalization among patients without COVID-19 were: acute heart failure (47%), bacterial
pneumonia (38.5%), and pulmonary embolism (9.2%). Overall, 67 (21.7%) patients of
COVID-19 group and 45 (13.1%) hospitalized for other causes were admitted to intensive
care unit; 30-day mortality was observed in 59 (19%) patients of COVID-19 group and 62
(18%) of non-COVID-19 group.
The multivariate analysis about risk factors for COVID-19 etiology at time of
hospitalization showed that dry cough (OR 3.76, CI 95% 1.98-7.92, P<0.001), duration of
fever>3 days (OR 5.21, CI 95% 2.34-9.21, P<0.001), lymphocytopenia (OR 1.98, CI 95%
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Accepted Manuscript
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1.27-4.22, P=0.002) and PaO2/FiO2 ratio<250 (OR 4.98, CI 95% 2.22-9.71, P<0.001) were
independently associated with COVID-19 etiology, while procalcitonin value>1 ng/ mL (OR
0.21, CI 95% 0.08-0.82, p<0.001), and lactate>2 mmol/L (OR 0.41, CI 95% 0.15-0.77,
p<0.001) were associated with non-COVID-19 etiology.
Finally, analysis about predictors of 30-day mortality showed that age (per-year
increase OR 1.33; CI 95% 1.11-2.10; p<0.001), cardiovascular disease (OR 4.58; CI 95%
2.07-8.25; p<0.001), and ICU admission (OR 2.1; CI 95% 1.48-4.4; p<0.001) were
independently associated with all-cause 30-day mortality, while the use of low-molecularweight heparin (OR 0.22, CI 95% 0.03-0.45, p=0.002) was associated with survival.
The findings of the present study can be summarized as follows:1) the prompt
identification of specific clinical characteristics (like dry cough or duration of fever>3 days),
and laboratory findings (like lymphocytopenia, PaO2/FiO2 ratio<250, procalcitonin value>1
ng/ mL, and lactate>2 mmol/L) can help physicians to distinguish rapidly between COVID19 or other etiologies [6]; 2) the application of a standard approach to management of
patients with acute respiratory failure and/or fever associated with the knowledge of clinical
and laboratory characteristics of COVID-19 can early drive physicians to therapeutic choices;
and 3) age, cardiovascular disease, and ICU admission show an independent association with
all-cause 30-day mortality [7], while the use of low-molecular-weight heparin was associated
with survival [8].
In conclusion, COVID-19 syndrome is characterized by a heterogeneous clinical,
laboratoristic, and radiological presentation, especially at its onset [