Even when adjusting for age, cancer history, lymphocyte, neutrophil, and platelet counts, lactate dehydrogenase level, serum creatinine, and corticosteroid treatment, elevated cystatin C levels were still an independent risk factor for disease severity (OR: 2.449, 95% CI: 1.565–3.831, and p < 0.001), unlike elevated creatinine levels on admission (Table 3). Here, CST3 is linked to cancer.