Early research into the implications concerning the evolution of the infection caused by the new coronavirus in people with glucose metabolism dysfunction, in this case diabetics, shows that severe forms of the disease predominate in this risk category. Moreover, it seems that even in patients with normal glycaemic status, COVID-19 may predispose to the development of hyperglycaemia which modulates immune mechanisms and inflammatory responses, with direct effects on morbidity and mortality. Thus, taking into account these scientific data, as well as the increased frequency of diabetes in the general population, we aimed to assess the risk of an unfavourable outcome of diabetic patients, which is in a strong connection with the presence and severity of pulmonary disease such as interstitial pneumonia/bronchopneumonia, as well as the effectiveness of Tocilizumab administration. The results of our study indicate a three-fold higher risk of death in patients with diabetes and COVID-19 (RR = 3.03; IC95%: 2.37-3.86; p = 0.001),compared to nondiabetic patients, and the risk of developing severe forms of acute respiratory failure was 1.5 times higher in the first studied category. In conclusion, we can say that the diabetic diagnosed with SARS-CoV-2 infection is more predisposed to immunological and organic dysfunctions that may ultimately result in death, and treatment with monoclonal anti-IL-6 antibodies was more effective in diabetic patients than non-diabetics (p < 0.05). The effectiveness of Tocilizumab was significant in both studied groups, but diabetic patients responded better to this therapy compared to non-diabetes-mellitus (DM) ones (76.7% vs. 35% p = 0.001).