The results of the multiple linear regression found a positive association between DII and CRP (β = 1.024, P < 0.001), hospitalization (β = 1.062, P < 0.001), WBC count (β = 0.486, P < 0.009), neutrophil count (β = 0.565, P < 0.001), and neutrophil-to-lymphocyte ratio (β = 0.538, P < 0.001) and a negative association between DII and the lymphocyte count (β = −0.569, P < 0.001) in patients with COVID-19 after adjusting for age, gender, literacy level, job, economic level, smoking, dietary supplement, drug history, disease history, BMI, and physical activity (Table 4). Here, CRP is linked to COVID-19.