Hospital trajectories and early predictors of clinical outcomes differ between SARS-CoV-2 and influenza pneumonia

Comparative Analysis of Clinical Outcomes Using Propensity Score Matching: Coronavirus Disease 2019 vs. Seasonal Influenza in Korea

BACKGROUND

The advent of the omicron variant and the formulation of diverse therapeutic strategies marked a new epoch in the realm of coronavirus disease 2019 (COVID-19). Studies have compared the clinical outcomes between COVID-19 and seasonal influenza, but such studies were conducted during the early stages of the pandemic when effective treatment strategies had not yet been developed, which limits the generalizability of the findings. Therefore, an updated evaluation of the comparative analysis of clinical outcomes between COVID-19 and seasonal influenza is requisite.

METHODS

This study used data from the severe acute respiratory infection surveillance system of South Korea. We extracted data for influenza patients who were infected between 2018 and 2019 and COVID-19 patients who were infected in 2021 (pre-omicron period) and 2022 (omicron period). Comparisons of outcomes were conducted among the pre-omicron, omicron, and influenza cohorts utilizing propensity score matching. The adjusted covariates in the propensity score matching included age, sex, smoking, and comorbidities.

RESULTS

The study incorporated 1,227 patients in the pre-omicron cohort, 1,948 patients in the omicron cohort, and 920 patients in the influenza cohort. Following propensity score matching, 491 patients were included in each respective group. Clinical presentations exhibited similarities between the pre-omicron and omicron cohorts; however, COVID-19 patients demonstrated a higher prevalence of dyspnea and pulmonary infiltrates compared to their influenza counterparts. Both COVID-19 groups exhibited higher in-hospital mortality and longer hospital length of stay than the influenza group. The omicron group showed no significant improvement in clinical outcomes compared to the pre-omicron group.

CONCLUSION

The omicron group did not demonstrate better clinical outcomes than the pre-omicron group, and exhibited significant disease severity compared to the influenza group. Considering the likely persistence of COVID-19 infections, it is imperative to sustain comprehensive studies and ongoing policy support for the virus to enhance the prognosis for individuals affected by COVID-19.

Use of Inhaled Epoprostenol in Patients With COVID-19 Receiving Humidified, High-Flow Nasal Oxygen Is Associated With Progressive Respiratory Failure

BACKGROUND

The clinical benefit of using inhaled epoprostenol (iEpo) through a humidified high-flow nasal cannula (HHFNC) remains unknown for patients with COVID-19.

RESEARCH QUESTION

Can iEpo prevent respiratory deterioration for patients with positive SARS-CoV-2 findings receiving HHFNC?

STUDY DESIGN AND METHODS

This multicenter retrospective cohort analysis included patients aged 18 years or older with COVID-19 pneumonia who required HHFNC treatment. Patients who received iEpo were propensity score matched to patients who did not receive iEpo. The primary outcome was time to mechanical ventilation or death without mechanical ventilation and was assessed using Kaplan-Meier curves and Cox proportional hazard ratios. The effects of residual confounding were assessed using a multilevel analysis, and a secondary analysis adjusted for outcome propensity also was performed in a multivariable model that included the entire (unmatched) patient cohort.

RESULTS

Among 954 patients with positive SARS-CoV-2 findings receiving HHFNC therapy, 133 patients (13.9%) received iEpo. After propensity score matching, the median number of days until the composite outcome was similar between treatment groups (iEpo: 5.0 days [interquartile range, 2.0-10.0 days] vs no-iEpo: 6.5 days [interquartile range, 2.0-11.0 days]; P = .26), but patients who received iEpo were more likely to meet the composite outcome in the propensity score-matched, multilevel, and multivariable unmatched analyses (hazard ratio, 2.08 [95% CI, 1.73-2.50]; OR, 4.72 [95% CI, 3.01-7.41]; and OR, 1.35 [95% CI, 1.23-1.49]; respectively).

INTERPRETATION

In patients with COVID-19 receiving HHFNC therapy, use of iEpo was associated with the need for invasive mechanical ventilation.

Comparison of hospitalized patients with severe pneumonia caused by COVID-19 and influenza A (H7N9 and H1N1): A retrospective study from a designated hospital

Considerable attention has been focused on the clinical features of coronavirus disease 2019 (COVID-19), but it is also important for clinicians to differentiate it from influenza virus infections. In the present study, the rate of coexisting disease was lower in the severe COVID-19 group than in the influenza A group (p = 0.003). Radiologically, severe COVID-19 patients had fewer instances of pleural effusion (p < 0.001). Clinically, severe COVID-19 patients had relatively better disease severity scores, less secondary bacterial infections, shorter times to beginning absorption on computed tomography, but longer durations of viral shedding from the time of admission (p < 0.05). Although the more severe influenza A patients required noninvasive respiratory support, these two groups ultimately yielded comparable mortalities. Based on the multiple logistic regression analysis, severe COVID-19 infection was associated with a lower risk of severe acute respiratory distress syndrome [odds ratio (OR) 1.016, 95% [confidence interval (CI)] 1.001-1.032, p = 0.041] and a better pneumonia severity index (OR 0.945, 95% [CI] 0.905-0.986, p = 0.009); however, these patients exhibited longer durations of viral shedding (OR 1.192, 95% [CI] 1.047-1.357, p = 0.008) than patients with severe influenza A infection. In conclusion, the conditions of severe influenza A patients appeared to be more critical than that of severe COVID-19 patients. However, relatively lower mortalities of these two severe cases are expected in the context of sufficient medical supplies.