Apparent Association of Insulin With Interleukin-6 (IL-6) in Severe COVID-19 Patients Having Chronic Disease Comorbidities

Background The severe acute respiratory syndrome caused by the novel coronavirus (COVID-19), due to its fast spread, is a disease with global health, social and economic burden. This is complicated by its high morbidity and mortality among those with medical comorbidities and older adults. During the outbreak in Libya, intensive care facilities were overwhelmed by the number of patients requiring special care. Admission to such facilities was reserved for severe cases showing low blood oxygen levels. Due to the inflammatory process in COVID-19, we believed it was essential to evaluate the outcome of inflammation reflected in the changes in interleukin-6 (IL-6) and insulin. Objective To study the changes in IL-6 and insulin during the course of the disease, if an association between them exists, and whether this association changes following seven days of treatment. Method We analyzed the data of 60 patients diagnosed with COVID-19 and admitted to the hospitals' Intensive Care Units (ICU) in the eastern part of Libya. The study was initiated on January 18th and concluded on March 22, 2021. Samples for the analysis were collected on the first day of admission and after seven days of hospitalization for patients who survived till the selected day. The collected samples were used to analyze IL-6 as an indicator of change in inflammation and insulin as a potential anti-inflammatory modulator. In addition, the association of insulin with IL-6 was statistically tested. Results Diabetes and hypertension, the most commonly observed chronic diseases in Libya, were found to represent the highest comorbidities among the ICU patients included in this study. Nonetheless, other diseases affected a smaller proportion of them, ranging from two patients for malignancy to 10 patients for cardiovascular disease. In addition, both age and gender showed differences in the number of ICU hospitalized patients and the death tally among them. The study showed that the IL-6 level was on the rise during the course of COVID-19, whereas that of insulin was on the decrease. The two variables showed an association for admission day samples as well as for samples after seven days of ICU hospitalization. Conclusion Although, IL-6 appears to play a predictive role in the development and outcome of severe COVID-19, along with other biochemical and clinical findings it could serve as an indicator of the disease outcome. On the other hand, the role of insulin as a complementary factor for alleviating inflammation remains to be fully understood and requires further research. There is a pressing necessity for establishing the mechanism through which insulin is associated with inflammation modulatory pathways, in particular through the pathways involving IL-6.