Background In the future, co-circulation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses A/B is likely. From a clinical point of view, differentiation of the two disease entities is crucial for patient management. We therefore aim to detect clinical differences between Coronavirus Disease 2019 (COVID-19) and seasonal influenza patients at time of hospital admission. Methods In this single-center observational study, we included all consecutive patients hospitalized for COVID-19 or influenza between November 2019 and May 2020. Data were extracted from a nationwide surveillance program and from electronic health records. COVID-19 and influenza patients were compared in terms of baseline characteristics, clinical presentation and outcome. We used recursive partitioning to generate a classification tree to discriminate COVID-19 from influenza patients. Results We included 96 COVID-19 and 96 influenza patients. Median age was 68 vs. 70 years ( p = 0.90), 72% vs. 56% ( p = 0.024) were males, and median Charlson Comorbidity Index (CCI) was 1 vs. 2 ( p = 0.027) in COVID-19 and influenza patients, respectively. Time from symptom onset to hospital admission was longer for COVID-19 (median 7 days, IQR 3–10) than for influenza patients (median 3 days, IQR 2–5, p < 0.001). Other variables favoring a diagnosis of COVID-19 in the classification tree were higher systolic blood pressure, lack of productive sputum, and lack of headache. The tree classified 86/192 patients (45%) into two subsets with ≥80% of patients having influenza or COVID-19, respectively. In-hospital mortality was higher for COVID-19 patients (16% vs. 5%, p = 0.018). Conclusion Discriminating COVID-19 from influenza patients based on clinical presentation is challenging. Time from symptom onset to hospital admission is considerably longer in COVID-19 than in influenza patients and showed the strongest discriminatory power in our classification tree. Although they had fewer comorbidities, in-hospital mortality was higher for COVID-19 patients. Supplementary Information The online version contains supplementary material available at 10.1186/s12879-021-05957-4.
【저자키워드】 COVID-19, SARS-CoV-2, Influenza, differences, Comparative, Classification tree, 【초록키워드】 coronavirus, Hospitalized, Mortality, Comorbidities, Influenza virus, outcome, sputum, headache, Surveillance, management, Patient, age, Hospital admission, Other, patients, in-hospital mortality, COVID-19 patients, Electronic health records, COVID-19 patient, Seasonal influenza, symptom onset, Systolic blood pressure, acute respiratory syndrome, supplementary material, baseline characteristics, Charlson Comorbidity Index, single-center, variable, time, males, discriminatory power, disease entity, Result, detect, lack, generate, median, subset, CCI, consecutive patient, diagnosis of COVID-19, IQR, 【제목키워드】 hospital, Patient, Seasonal influenza, single center,