Gliptins vs. the Alternatives for Type 2 Diabetes

Dipeptidyl peptidase-4 inhibitors (e.g., Januvia, Onglyza, Tradjenta), also known as “gliptins,” are oral hypoglycemic drugs that raise blood incretin levels, thereby inhibiting glucagon release and lowering blood-glucose levels. In a meta-analysis involving 14,000 adults with type 2 diabetes, investigators compared gliptins with metformin (8 monotherapy trials) and, in the context of concomitant metformin therapy, with other hypoglycemic agents (11 combination-therapy trials).

Compared with metformin monotherapy, gliptin use conferred a smaller reduction in glycosylated hemoglobin (HbA_1c) levels (mean difference, 0.2%), more-frequent failure to achieve HbA_1c levels <7%, and less weight loss (mean difference, 1.5 kg). However, gliptin recipients were less likely than metformin recipients to discontinue therapy because of adverse events. All differences were statistically significant.

With concomitant metformin, gliptins were less effective in lowering HbA_1c than sulfonylureas, glucagon-like peptide-1 (GLP-1) agonists, or pioglitazone. Gliptins yielded more weight loss than a sulfonylurea or pioglitazone (mean differences: 1.9 kg and 3.0 kg, respectively) but less weight loss than a GLP-1 agonist (mean difference, 1.6 kg). All differences were statistically significant. Hypoglycemia occurred less often with a gliptin plus metformin than with a sulfonylurea plus metformin.