Severity of respiratory failure at admission and in-hospital mortality in patients with COVID-19: a prospective observational multicentre study

Abstract

ObjectivesCOVID-19 causes lung parenchymal and endothelial damage that lead to hypoxic acute respiratory failure (hARF). The influence of hARF severity on patients’ outcomes is still poorly understood.DesignObservational, prospective, multicentre study.SettingThree academic hospitals in Milan (Italy) involving three respiratory high dependency units and three general wards.ParticipantsConsecutive adult hospitalised patients with a virologically confirmed diagnosis of COVID-19. Patients aged <18 years or unable to provide informed consent were excluded.InterventionsAnthropometrical, clinical characteristics and blood biomarkers were assessed within the first 24 hours from admission. hARF was graded as follows: severe (partial pressure of oxygen to fraction of inspired oxygen ratio (PaO2/FiO2) <100 mm Hg); moderate (PaO2/FiO2 101–200 mm Hg); mild (PaO2/FiO2 201–300 mm Hg) and normal (PaO2/FiO2 >300 mm Hg).Primary and secondary outcome measuresThe primary outcome was the assessment of clinical characteristics and in-hospital mortality based on the severity of respiratory failure. Secondary outcomes were intubation rate and application of continuous positive airway pressure during hospital stay.Results412 patients were enrolled (280 males, 68%). Median (IQR) age was 66 (55–76) years with a PaO2/FiO2 at admission of 262 (140–343) mm Hg. 50.2% had a cardiovascular disease. Prevalence of mild, moderate and severe hARF was 24.4%, 21.9% and 15.5%, respectively. In-hospital mortality proportionally increased with increasing impairment of gas exchange (p<0.001). The only independent risk factors for mortality were age ≥65 years (HR 3.41; 95% CI 2.00 to 5.78, p<0.0001), PaO2/FiO2 ratio ≤200 mm Hg (HR 3.57; 95% CI 2.20 to 5.77, p<0.0001) and respiratory failure at admission (HR 3.58; 95% CI 1.05 to 12.18, p=0.04).ConclusionsA moderate-to-severe impairment in PaO2/FiO2 was independently associated with a threefold increase in risk of in-hospital mortality. Severity of respiratory failure is useful to identify patients at higher risk of mortality.Trial registration numberNCT04307459

Clinical Characteristics and Short-Term Outcomes of Chronic Dialysis Patients Admitted for COVID-19 in Metro Manila, Philippines

“…While these findings need to be confirmed in a larger study cohort of ESKD patients, they seem to be consistent with later reports involving a big study population. 23 , 24 …”

Characteristics and outcomes in hospitalized COVID-19 patients during the first 28 days of the spring and autumn pandemic waves in Milan: An observational prospective study

“…Less advanced disease stages, a lower number of patients with severe aRF at admission and an increased proportion of patients treated with anticoagulant therapy may have thus contributed to decreased mortality [ 14 , 15 ]. In fact, PaO2/FiO2<200 mmHg [ 10 ] and D-dimer >2.000 FEU [ 12 ] were demonstrated to be independent risk factors for adverse outcomes, while the increased use of systemic corticosteroids [ 6 , 7 , 14 ] and anticoagulation [ 13 , 14 ] showed a reduction in mortality in patients with severe COVID-19 pneumonia.…”

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Association of inhaled and systemic corticosteroid use with Coronavirus Disease 2019 (COVID-19) test positivity in patients with chronic pulmonary diseases

“…However, our findings may be applied to patients with chronic pulmonary diseases Third, we do not have sufficient information about the dosage or duration of medication use and cannot assess how those might have affected the likelihood of testing positive for COVID-19 Fourth, the mean age of our study population is relatively young (53 years old) which may not be representative of the total population. This may be an important confounder and limitation to our study results since age is an independent factor of COVID severity and mortality [ 29 ]. Finally, similar to other electronic medical research, non-differential misclassification of binary variables may reduce the power of detecting a true association.…”