ImportanceInfection 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 ObjectiveTo compare case-fatality between ARDS-Covid-19 and ARDS-Influenza A (H1N1), adjusting for known prognostic
risk factors. Design, Setting and ParticipantsOne 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. ResultsPatients 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 PaO2/FIO2. 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. CONCLUSIONCOVID-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. QuestionIs the
mortality of ARDS associated with Covid-19 greater than that of ARDS associated to
influenza H1N1? FindingsIn 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. MeaningCOVID-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