In this network meta-analysis of 31 observational studies with more than 3.6 million patients, sodium-glucose cotransporter-2 inhibitors were associated with lower risk of COVID-19–related adverse outcomes in diabetes, followed by glucagon-like peptide-1 receptor agonists and metformin, compared with insulin, dipeptidyl peptidase-4 inhibitors, secretagogues, and glucosidase inhibitors. Here, SLC5A2 is linked to COVID-19.