A recent study demonstrated widespread substitution of analog for human insulin and rising out-of-pocket costs in privately insured people with type 2 diabetes in the United States.1 Medicaid reimbursements have increased for both human insulin and more costly analog insulins.2 Although studies have described per-person changes in excess medical spending of US adults with diabetes on prescription medications,3 they have not reported trends in expenditures for different classes of antihyperglycemic medications that simultaneously consider changes in use and price.