Underlying mechanisms of inflammation may help anticipate clinical trajectories of COVID-19

Rapid changes in a biomarker of inflammation may be a key predictor of novel coronavirus (COVID-19) outcomes, according to a new study published in the journal Cell Reports Medicine.  

Researchers from Brigham and Women's Hospital in Boston, Massachusetts analyzed patients' levels of inflammation, known to be associated with severity of illness, by looking at C-reactive protein (CRP) trends in 100 COVID-19 patients admitted to the hospital. They found that a rapid rise in CRP levels during the first 48 to 72 hours of hospitalization was predictive of subsequent respiratory deterioration and intubation, while steadier CRP levels were observed in patients whose condition remained stable.

Inflammation is a broad term that describes the release of chemicals involved in immune responses. CRP tests integrate signals from several different proteins involved in inflammation, called cytokines, to provide physicians with a snapshot of a patient's inflammatory activity within a matter of hours. Other tests, like cytokine assays, can provide more specific information about which proteins may be active in inflammatory pathways, but these tests can take one to two days to process, and COVID-19 patients' conditions can worsen before the results are received, the researchers said.

CRP tests can therefore serve as a practical addition to standard protocols for assessing the anticipated clinical trajectories of COVID-19 patients, according to the study.

The results also provide insight into the underlying mechanisms at play in COVID-19 infections, the researchers said. An increase in a cytokine called IL-6 during the first 24-48 hours was correlated to CRP levels and the progression of the disease. Alternatively, while CRP is associated with IL-6, CRP can reflect other inflammatory pathways besides IL-6, so targeting other inflammatory cytokines or pathways besides IL-6 could be considered, the researchers said.

The researchers said they hope that the findings will help frontline healthcare workers better understand the volatility of COVID-19 patients' conditions.

"Doctors' and nurses' clinical instincts about COVID-19 are not fully developed because the disease is still so new," said Edy Yong Kim, MD, PhD, corresponding author of the study of the Division of Pulmonary and Critical Care Medicine at the Brigham and Women's Hospital, in a statement. "But when we showed these results to frontline doctors and nurses at the Brigham, they felt like it matched what they intuitively saw in the spring. It's always nice to hear that what you do in the lab reflects what goes on in the real world, too."

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