The results showed that age (OR 1.067; 95% CI 1.034–1.101; P < 0.001), diabetes mellitus (OR 9.154; 95% CI 2.710–30.926; P < 0.001), CD3+ T cell counts (OR 0.996; 95% CI 0.994–0.997; P < 0.001), and IL–6 (OR 1.006; 95% CI 1.000–1.013; P = 0.039) on hospital admission were risk factors of ICU cases with COVID-19. This evidence concerns the gene IL6 and COVID-19.