COVID-19 and diabetes: Is there enough evidence?

The pandemic of COVID-19, a disease caused by a novel coronavirus SARS-CoV-2, is associated with significant morbidity and mortality. Recent data showed that hypertension, diabetes mellitus, cardiovascular diseases, and chronic obstructive pulmonary disease were the most prevalent comorbidities in COVID-19 patients. Additionally, data indicate that hypertension, diabetes, and cardiovascular diseases are important risk factors for progression and unfavorable outcome in COVID-19 patients. There is only limited amount of data regarding follow-up of these patients, and they provided conflicting results. The main limitation is a small number of participants and particularly those who experienced primary composite outcome (admission in intensive care unit, use of mechanical ventilation, or death). Additionally, the limited number of patients was essential obstacle for performing analysis that would include many confounding factors such as advanced age, smoking status, and obesity and potentially change conclusion. So far, there is no study that demonstrated independent predictive value of diabetes on mortality in COVID-19 patients, but there are many speculations about the association between diabetes and susceptibility to novel coronavirus, as well as its impact on progression and prognosis of COVID-19. The aim of this review article was to summarize the current knowledge about the relationship between diabetes and COVID-19 and its role in outcome in these patients.