Schematic diagram depicting the putative association between severe COVID-19 and the indicated preexisting chronic diseases and affected organs. The blue line indicates the association between preexisting chronic diseases and COVID-19 severity. The red line indicates organ injuries observed in COVID-19 patients. Expression of ACE2 in the indicated organs is indicated. ACE2: angiotensin-converting enzyme 2; ALT: alanine transaminase; AST: aspartate aminotransferase; BUN: blood urea nitrogen; CK-MB: creatine kinase-MB; cTnI: cardiac troponin I; CVD: cardiovascular disease.