Moreover, the results revealed that several kinds of chronic disease, such as chronic renal disease, chronic obstructive pulmonary disease, and chronic liver disease, could also increase the level of IL-6 and the severity of the COVID-19 infection (Figure 2), and that patients with cardiovascular disease had higher IL-6 levels and were susceptible to disease progression (Figure 2). Here, IL6 is linked to chronic obstructive pulmonary disease.