A Comparison of Demographic, Epidemiological and Clinical Characteristics of Hospital Influenza-related Viral Pneumonia Patients

Abstract

Background The comparison of the demographic, epidemiological, and clinical characteristics of hospital human influenza (influenza A (H1N1) pdm09, H3N2, and B) -related and hospitalized avian-origin influenza A (H7N9)-related viral pneumonia patients has not been reported. Methods A retrospective study was conducted in hospitalized influenza-related viral pneumonia patients. Results The average age of hospitalized human influenza A -related viral pneumonia patients was lower than B pneumonia patients(p<0.05), human influenza A -related patients in the 35–49-year-old group were more than those with B pneumonia patients (p<0.05), and relatively less in the ≥65-year-old group than B pneumonia patients (p=0.079). The proportion of patients who have at least one comorbid condition to human influenza A pneumonia was lower than B and H7N9 pneumonia (p<0.05). The proportion of invasive mechanical ventilation (IMV), lymphocytopenia, elevated lactate dehydrogenase, and d-dimer to hospitalized human influenza A-related viral pneumonia patients was higher than B pneumonia patients (p<0.05), but lower than H7N9 pneumonia patients (p<0.05). Conclusions Hospital influenza B-related viral pneumonia mainly affects the elderly and people with underlying diseases, while human influenza A pneumonia mainly affects the young adults; however, the mortality was similar. The proportion of severe cases to hospital human influenza A-related viral pneumonia patients was higher than those of B pneumonia patients but lower than H7N9 pneumonia patients. Pulmonary consolidation and positive bacterial culture (sputum) were independently associated with IMV, while shock, white blood cell count >10,000/mm 3 , and positive bacterial culture (blood or sputum) were independently associated with death to three types hospitalized influenza-related viral pneumonia patients.