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Comparison of Hospitalized Patients With ARDS Caused by COVID-19 and H1N1

Xiao Tang¹, Rong-Hui Du², Rui Wang¹

¹Department of Respiratory and Critical Care Medicine, Beijing Chao-Yang Hospital, Capital Medical University, Beijing Institute of Respiratory Medicine, Beijing Engineering Research Center for Diagnosis and Treatment of Respiratory and Critical Care Medicine (Beijing Chao-Yang Hospital), Beijing Key Laboratory of Respiratory and Pulmonary Circulation Disorders, Beijing, China.

|April 1, 2020

Insights

This study found distinct clinical differences between COVID-19 and H1N1 pneumonia in patients with ARDS. COVID-19 patients exhibited less severe illness and lower mortality rates compared to H1N1 cases.

Area of Science:

Pulmonology
Infectious Diseases
Critical Care Medicine

Background:

Distinguishing coronavirus disease 2019 (COVID-19) from other respiratory infections like influenza is crucial for effective clinical management.
Influenza A (H1N1) pneumonia presents a significant differential diagnosis challenge for patients with acute respiratory distress syndrome (ARDS).

Purpose of the Study:

To compare the clinical presentations, imaging characteristics, treatments, and prognosis of patients with ARDS caused by COVID-19 versus influenza A (H1N1).

Main Methods:

A retrospective case-control study comparing two cohorts of ARDS patients: COVID-19 (n=73) and H1N1 (n=75).
Analysis included clinical manifestations, imaging findings, therapeutic interventions, and patient outcomes.

Main Results:

COVID-19 patients were older and had more nonproductive cough, fatigue, and GI symptoms. H1N1 patients presented with higher Sequential Organ Failure Assessment (SOFA) scores and lower Pao2/Fio2 ratios.
Ground-glass opacities were more prevalent in COVID-19 patients. While in-hospital mortality was similar, SOFA score-adjusted mortality was significantly higher in the H1N1 cohort.

Conclusions:

Significant differences exist in the clinical and radiological presentations of COVID-19 and H1N1-induced ARDS.
COVID-19 patients with ARDS demonstrated less severe illness upon presentation and experienced lower SOFA score-adjusted mortality compared to H1N1 patients.

Read full analysis

Abstract

Background:

Since the outbreak of coronavirus disease 2019 (COVID-19) in China in December 2019, considerable attention has been focused on its elucidation. However, it is also important for clinicians and epidemiologists to differentiate COVID-19 from other respiratory infectious diseases such as influenza viruses.

Research Question:

The aim of this study was to explore the different clinical presentations between COVID-19 and influenza A (H1N1) pneumonia in patients with ARDS.

Study Design And Methods:

This analysis was a retrospective case-control study. Two independent cohorts of patients with ARDS infected with either COVID-19 (n = 73) or H1N1 (n = 75) were compared. Their clinical manifestations, imaging characteristics, treatments, and prognosis were analyzed and compared.

Results:

The median age of patients with COVID-19 was higher than that of patients with H1N1, and there was a higher proportion of male subjects among the H1N1 cohort (P < .05). Patients with COVID-19 exhibited higher proportions of nonproductive coughs, fatigue, and GI symptoms than those of patients with H1N1 (P < .05). Patients with H1N1 had higher Sequential Organ Failure Assessment (SOFA) scores than patients with COVID-19 (P < .05). The Pao₂/Fio₂ of 198.5 mm Hg in the COVID-19 cohort was significantly higher than the Pao₂/Fio₂ of 107.0 mm Hg in the H1N1 cohort (P < .001). Ground-glass opacities was more common in patients with COVID-19 than in patients with H1N1 (P < .001). There was a greater variety of antiviral therapies administered to COVID-19 patients than to H1N1 patients. The in-hospital mortality of patients with COVID-19 was 28.8%, whereas that of patients with H1N1 was 34.7% (P = .483). SOFA score-adjusted mortality of H1N1 patients was significantly higher than that of COVID-19 patients, with a rate ratio of 2.009 (95% CI, 1.563-2.583; P < .001).

Interpretation:

There were many differences in clinical presentations between patients with ARDS infected with either COVID-19 or H1N1. Compared with H1N1 patients, patients with COVID-19-induced ARDS had lower severity of illness scores at presentation and lower SOFA score-adjusted mortality.

Keywords:

ARDS COVID-19 H1N1 influenza A mortality

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