This systematic review of reviews found that diabetes is associated with a higher risk of mortality, ICU admission, and possibly case severity related to COVID-19. A small amount of evidence pointed to higher risk associated with type 1 diabetes (as opposed to type 2), hyperglycemia, and not using metformin prior to hospitalization. The evidence is also consistent with, although does not establish, the possibility that people with diabetes are more likely to develop COVID-19 following SARS-CoV-2 infection.