Interleukin-6 as a Potential Predictor of COVID-19 Disease Severity in Hospitalized Patients and its Association with Clinical Laboratory Routine Tests

Background: Researchers have already reported a high level of interleukin (IL)-6 in patients affected by Coronavirus Disease 2019 (COVID-19). In this study, we investigated the surge of IL-6 level and its association with the clinical and paraclinical markers in these patients. Materials and Methods: The study sample comprised 205 confirmed hospitalized patients with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and 70 healthy volunteer individuals. Routine laboratory examinations, including hematology, biochemistry, and hormone analysis, as well as IL-6 level measurement, were conducted. The patients grouped into 5 based on their IL-6 levels. Then, they were compared with regard to their need for mechanical ventilator and clinical laboratory routine tests. Results: IL-6 levels were significantly higher in hospitalized patients compared with healthy individuals (P<0.001). The IL-6 level was approximately 10-fold of the normal range in 22.9% of the patients. Also, more than 56.1% of them signify IL-6 over 3-fold of the normal range. IL-6