Comparison between Patients Hospitalized with Influenza and COVID-19 at a Tertiary Care Center.

ABSTRACT

BACKGROUND: Widespread reports suggest the characteristics and disease course of coronavirus disease 2019 (COVID-19) and influenza differ, yet detailed comparisons of their clinical manifestations are lacking. OBJECTIVE: Comparison of the epidemiology and clinical characteristics of COVID-19 patients during the pandemic with those of influenza patients in previous influenza seasons at the same hospital DESIGN: Admission rates, clinical measurements, and clinical outcomes from confirmed COVID-19 cases between March 1 and April 30, 2020, were compared with those from confirmed influenza cases in the previous five influenza seasons (8 months each) beginning September 1, 2014. SETTING: Large tertiary care teaching hospital in Boston, MA PARTICIPANTS: Laboratory-confirmed COVID-19 and influenza inpatients MEASUREMENTS Patient demographics and medical history, mortality, incidence and duration of mechanical ventilation, incidences of vasopressor support and renal replacement therapy, and hospital and intensive care admissions. RESULTS: Data was abstracted from medical records of 1052 influenza patients and 582 COVID-19 patients. An average of 210 hospital admissions for influenza occurred per 8-month season compared to 582 COVID-19 admissions over 2 months. The median weekly number of COVID-19 patients requiring mechanical ventilation was 17 (IQR 4, 34) compared to a weekly median of 1 (IQR 0, 2) influenza patient (p=0.001). COVID-19 patients were significantly more likely to require mechanical ventilation (31% vs 8%) and had significantly higher mortality (20% vs. 3%; p<0.001 for all). Relatively more COVID-19 patients on mechanical ventilation lacked pre-existing conditions compared with mechanically ventilated influenza patients (25% vs 4%, p<0.001). Pneumonia/ARDS secondary to the virus was the predominant cause of mechanical ventilation in COVID-19 patients (94%) as opposed to influenza (56%). LIMITATION: This is a single-center study which could limit generalization. CONCLUSION: COVID-19 resulted in more weekly hospitalizations, higher morbidity, and higher mortality than influenza at the same hospital.