CRP and diabetes mellitus: Coronavirus disease-19 patients, with pre-existing DM, have shown to have higher serum interleukin-6 (IL-6), C-reactive protein (CRP), and ferritin levels than those without DM.10 Cariou et al11 found out that 1 in 5 patients with DM were intubated and mechanically ventilated within the same length of time.