Comparison of the Clinical Characteristics and Severity of Influenza and Non-influenza Respiratory Virus-Related Pneumonia in China: A Multicenter, Real-World Study

Purpose Respiratory viruses are important etiologies of community-acquired pneumonia (CAP). However, the impact of different RVs on the outcomes of CAP is not well elucidated. This study aims to compare the clinical features and severity of influenza (Flu-p) and non-influenza respiratory viruses-related pneumonia (NIRVs-p) onset in the community among immunocompetent adults. Methods The data of the patients hospitalized with laboratory-confirmed RVs-p were retrospectively reviewed from five teaching hospitals in China from January 2013 to May 2019. Univariate and multivariate logistic regressions were performed to compare the clinical characteristics and outcomes between Flu-p and NIRVs-p. Results A total of 1079 patients with Flu-p and 341 patients with NIRVs-p were included in this study. A multivariate logistic regression model revealed chronic pulmonary disease [odd ratio (OR) 0.341, 95% confidence interval (CI) 0.225-0.515, p < 0.001], solid malignant tumor (OR 0.330, 95% CI 0.163-0.668, p = 0.002), myalgia (OR 1.697, 95% CI 1.236-2.330, p < 0.001), lymphocytes <0.8×109/L (OR 10.811, 95% CI 6.949-16.818, p < 0.001) and blood albumin <35 g/L (OR 0.327, 95% CI 0.242-0.442, p < 0.001) were predictors for Flu-p. After adjusting for confounders, the multivariate logistic regression analysis confirmed that influenza B-related pneumonia (FluB-p) (OR 0.419, 95% CI 0.272-0.646, p < 0.001) and NIRVs-p (OR 0.260, 95% CI 0.158-0.467, p < 0.001) were associated with a decreased risk of 30-day mortality compared with the influenza A-related pneumonia (FluA-p). Conclusion Our results showed that patients with FluA-p experience a more severe disease than those with FluB-p and NIRVs-p. Some clinical features are helpful to distinguish between NIRVs-p and Flu-p.