Anemia was the strongest predictor in association with COVID-19 (β = 3.65, CI = 1.46–5.39, p-value < 0.001), followed by elevated CRP (β = 2.11, CI = 1.20–3.06, p-value < 0.001), and respectively IL-6 (β = 1.92, CI = 1.20–2.47, p-value = 0.001). This evidence concerns the gene IL6 and anemia (phenotype).