In a new study, researchers at Northwestern University in Chicago hypothesize that the deaths of patients with Covid-19 are not caused by cytokine stormbut from one secondary bacterial pneumonia not resolved. Since the whole world has been hit by the terrible Covid-19 pandemic, scientists from all over the world have been trying to understand what causes the deaths of Covid-19 patients. This study, published in the Journal of Clinical Investigation, argues that the cause of the death is not the so-called “cytokine storm”, as previously thought. Instead, the leading cause of death appears to be secondary bacterial pneumonia, affecting nearly half of Covid-19 patients who require mechanical ventilation support. To arrive at this hypothesis, the research team used machine learning to analyze patient medical data.
The technique used is called CarpeDiem and groups the days of hospitalization of intensive care unit (ICU) users in similar clinical states, based on data from electronic medical records. This approach has made it possible to understand how complications, such as bacterial pneumonia, influence the course of the disease. The study analyzed 585 Northwestern Memorial Hospital ICU patients with severe pneumonia and respiratory failure, of which 190 affected by Covid-19. It has emerged that nearly half of patients with Covid-19 develop mechanically ventilated bacterial pneumonia. Additionally, the researchers found that those who were treated for secondary pneumonia had a better chance of surviving than those whose pneumonia did not resolve. Second Benjamin Singer, author of the study, “our data suggest that mortality related to the virus itself is relatively low, but other things compensate for that mortality, much like secondary bacterial pneumonia.”
The study therefore refutes the cytokine storm theory, which was thought to be responsible for the deaths of patients with Covid-19. Cytokine storm is an exaggerated inflammatory reaction that causes organs such as the lungs, kidneys and brain to fail. However, according to Singer, “if the cytokine storm were the main reason for the long stay in the ICU of patients with COVID-19, we would expect to see frequent transitions to states characterized by multiple organ dysfunction. But that’s not what we saw”, comments the US researcher.
Lella Simone