Hypoglycemia and acute metabolic complications (AMCs; ketoacidosis, hyperosmolarity, and coma) are glycemic outcomes that have high cost and high morbidity; these outcomes must be taken into consideration when choosing initial second-line therapy after metformin. We conducted a retrospective cohort study analyzing national administrative data from adults with type 2 diabetes mellitus who started a second-line diabetes medication (sulfonylureas [SFUs], thiazolidinediones [TZDs], glucagon-like peptide 1 [GLP-1] agonists, dipeptidyl peptidase 4 [DPP-4] inhibitors, basal insulin, or sodium-glucose contransporter 2 [SGLT-2] inhibitors) between April 1, 2011 and September 30, 2015 (N=43,288) and compared rates of hypoglycemia and AMCs.