Clinical presentation differs with COVID-19-, H1N1-related ARDS

Among patients with acute respiratory distress syndrome, those with COVID-19, as compared with influenza A H1N1-related pneumonia, had different clinical manifestations of the disease and also appeared to have less severity of disease and lower adjusted mortality, researchers reported in Chest.

“Although these two respiroviruses have loomed as epidemics in different regions at present, such epidemics can easily propagate to further regions over time due to climate change and global travel by individuals. Because of their distinct treatments and prognoses, it is important for clinicians and epidemiologists to accurately identify these two respiroviral infections via their differential clinical manifestations,” they wrote. “Therefore, the aim of this study was to compare the different clinical presentations between ARDS patients infected with COVID-19 vs. H1N1 in order to provide some guidance for their differential diagnoses.”

To learn more, the researchers conducted a retrospective case-control study comparing clinical presentations, imaging characteristics, treatments and prognoses of two cohorts of patients with ARDS. One cohort included 73 patients with COVID-19 hospitalized at Wuhan Pulmonary Hospital from Dec. 24, 2019, to Feb. 7, 2020. The second included 75 patients with H1N1 pneumonia who were hospitalized at Beijing Chao-Yang Hospital from March 2016 to December 2019.

Overall, results showed that patients with COVID-19 vs. H1N1 were generally older (median age, 67 vs. 52 years; P < .001) and were more likely to have septic shock at admission (31.5% vs. 13.3%; P < .001), although they had lower median sequential organ failure assessment (SOFA; 2 vs. 5) and Acute Physiology and Chronic Health Evaluation (APACHE) II scores (11 vs. 14; P < .001).

In terms of symptoms, fever, cough and dyspnea were common among both patients with COVID-19 and H1N1. However, patients with COVID-19, as compared with H1N1, were less likely to have productive cough (53.4% v.78.7%; P = .002) and more likely to have fatigue (63% vs. 18.7%; P < .001), myalgia (37% vs. 6.7%; P < .001) and gastrointestinal symptoms (34.2% vs. 14.7%; P = .007).

Additionally, the median ratio of partial pressure of oxygen to fractional inspired oxygen was higher for patients with ARDS and COVID-19 vs. H1N1 (198.2 mm Hg vs. 107 mm Hg; P < .001).

Chest CT also revealed differences between the two study cohorts, with ground-glass opacities appearing more often among patients with COVID-19 (94.5% vs. 45.3%; P <. 001) and consolidation appearing more often among patients with H1N1 (P = .042).

Treatment also differed significantly between the two groups. Patients with COVID-19 received a greater variety of antiviral therapies than those with H1N1. Glucocorticoids were also administered to 79.5% of patients with COVID-19 compared with 49.3% of those with H1N1. For respiratory support, 67.1% of patients with COVID-19 received conventional oxygen therapy as initial support and 89.7% of patients with H1N1 received mechanical ventilation (P <.001).

By the study’s publication, 17.6% of the patients with COVID-19 remained hospitalized. Overall, 28.8% of the patients with COVID-19 and 34.7% of the patients with H1N1 died (P = .483). After adjustment for SOFA score, mortality was significantly higher among those with H1N1 vs. COVID-19 (rate ratio = 2.009; 95% CI, 1.563-2.583).

The researchers acknowledged several study limitations, including its retrospective design, the use of two independent single-center cohorts and the greater severity of the patients with H1N1. They also noted that more than one-third of patients with COVID-19 were still hospitalized at the time of manuscript submission and the overall mortality rate may therefore be underestimated.

“Future studies investigating COVID-19 should focus on well-designed, prospective, case-control trials with large sample sizes, which could provide more experience and evidence in regard to COVID-19 treatment measures,” the researchers wrote. – by Melissa Foster

Disclosures: The authors report no relevant financial disclosures.