The role of interleukin‐6 in monitoring severe case of coronavirus disease 2019

Progression to severe disease is a difficult problem in treating coronavirus disease 2019 (COVID‐19). The purpose of this study is to explore changes in markers of severe disease in COVID‐19 patients. Sixty‐nine severe COVID‐19 patients were included. Patients with severe disease showed significant lymphocytopenia. Elevated level of lactate dehydrogenase (LDH), C‐reactive protein (CRP), ferritin, and D‐dimer was found in most severe cases. Baseline interleukin‐6 (IL‐6) was found to be associated with COVID‐19 severity. Indeed, the significant increase of baseline IL‐6 was positively correlated with the maximal body temperature during hospitalization and with the increased baseline of CRP, LDH, ferritin, and D‐dimer. High baseline IL‐6 was also associated with more progressed chest computed tomography (CT) findings. Significant decrease in IL‐6 and improved CT assessment was found in patients during recovery, while IL‐6 was further increased in exacerbated patients. Collectively, our results suggest that the dynamic change in IL‐6 can be used as a marker for disease monitoring in patients with severe COVID‐19.