ELEVATED INTERLEUKIN-6 LEVELS IN COVID-19-INFECTED PATIENTS ARE ASSOCIATED WITH MAJOR ADVERSE CARDIAC EVENTS AND/OR MORTALITY

Background

As the COVID-19 pandemic continues, awareness of cardiovascular complications has been brought to light in regards to major adverse cardiac events (MACE). Inflammatory cytokine markers such as interleukin-6 (IL-6) are produced in response to infection and tissue injury, which may correlate to disease severity in COVID-19 patients. However, studies have not shown an association between elevated IL-6 levels and cardiovascular outcomes, particularly MACE and/or mortality.

Methods

From March to May 2020, a retrospective chart review was performed on 496 patients who tested positive for COVID-19 among four hospitals in one health system, one of which included a major quaternary hospital. Patient baseline characteristics, cases of MACE/mortality, and their respective IL-6 levels were identified. Analyses were done to identify any correlation between IL-6 levels and incidence of MACE and/or mortality. MACE was defined as a composite of myocardial infarction, stroke, deep venous thrombosis/pulmonary embolism, or shock requiring vasopressor support. Elevated IL-6 was defined as >5 pg/ml.

Results

Of the 496 patients hospitalized with COVID-19, 191 patients had an IL-6 level drawn and 68% had an elevated IL-6 level. The elevated IL-6 population had a 5.9 times higher odds of developing MACE compared to the normal IL-6 population (p=<0.0001, 95% CI = 2.65-14.11). The elevated IL-6 population also had higher odds of mortality compared to the normal IL-6 population (28.2% vs 5%, p=0.0001, OR=7.47, 95% CI=2.19-39.32). Also, the elevated IL-6 population had higher odds of having a worse outcome (MACE and/or mortality) compared to the normal IL-6 population (58.78% vs 20.00%, p<0.0001, OR=5.7, 95% CI 2.65-12.83).

Conclusion

Elevated IL-6 levels in COVID-19 patients were associated with MACE and/or mortality. It is advisable to obtain and monitor IL-6 levels in all COVID-19-infected patients to help risk stratify patients who would require a higher level of care.