Comparison of the clinical characteristics and mortality in ARDS due to COVID-19 versus ARDS due to Influenza A-H1N1pdm09

Importance Infection with the SARS-Cov-2 and Influenza A-H1N1 viruses is responsible for the first pandemics of the 21st century. Both of these viruses can cause severe pneumonia and acute respiratory distress syndrome (ARDS). The clinical differences and mortality associated with these two pandemic pneumonias in patients with ARDS are not well established Objective To compare case-fatality between ARDS-Covid-19 and ARDS-Influenza A (H1N1), adjusting for known prognostic risk factors. Design, Setting and Participants One hundred forty-seven patients with COVID-19 were compared with 94 with Influenza A-H1N1, all of these were admitted to the intensive care unit of the Referral Center for Respiratory Diseases and COVID-19 in Mexico City and fulfilled the criteria of ARDS. Results Patients arrived at the hospital after 9 days of symptoms. Influenza patients had more obesity, more use of Norepinephrine, and higher levels of lactic dehydrogenase and glucose, and fewer platelets and lower PaO 2 /FIO 2 . Crude mortality was higher in COVID than in influenza (39% vs. 22%; p = 0.005). In a Cox proportional hazard model, patients with a diagnosis of COVID-19 had a hazard ratio (HR) = 3.7; 95% Confidence Interval [CI] = 1.9-7.4, adjusted for age, gender, sequential organ failure assessment (SOFA) score, ventilatory ratio, and prone ventilation. In the fully adjusted model, the ventilatory ratio and the absence of prone-position ventilation were also predictors of mortality. CONCLUSION COVID-19 patients treated in an intensive care unit (ICU) had a 3.7 times higher risk of death than similar patients with Influenza A-H1N1, after adjusting for SOFA score and other relevant risk factors for mortality. Question Is the mortality of ARDS associated with Covid-19 greater than that of ARDS associated to influenza H1N1? Findings In a Cox proportional hazard model, patients with a diagnosis of COVID-19 had a hazard ratio (HR) = 3.7; 95% Confidence Interval [CI] = 1.9-7.4, adjusted for age, gender, sequential organ failure assessment (SOFA) score. Meaning COVID-19 patients treated in an intensive care unit (ICU) had a 3.7 times higher risk of death than similar patients with Influenza A-H1N1