One interesting connection is that patients with hypertension and diabetes are usually treated with angiotensin-converting enzyme (ACE) inhibitors and angiotensin II type-I receptor blockers (ARBs), that induce the expression of ACE2 (the cellular receptor for SARS-CoV-2), thus likely to aggravate the disease course of COVID-19 [22]. This evidence concerns the gene ACE2 and diabetes mellitus.