Sitagliptin compared with thiazolidinediones as a third-line oral antihyperglycemic agent in type 2 diabetes mellitus.

OBJECTIVE: To compare sitagliptin and thiazolidinediones as third-line oral antihyperglycemic agents among ethnic minority patients with poorly controlled type 2 diabetes mellitus.

METHODS: In an open-label, single-arm design, we treated type 2 diabetic patients who had suboptimal diabetes control on maximum tolerated dosages of metformin plus sulfonylureas with the addition of sitagliptin, 100 mg daily, and compared their responses with findings from a historical control group of similar patients treated with rosiglitazone, 8 mg daily, or pioglitazone, 45 mg daily, as their third-line oral agent. Patients were assessed bimonthly, and those who achieved hemoglobin A1c levels less than 7.5% at 4 months continued through 1 year of follow-up.

RESULTS: One hundred eight patients were treated with sitagliptin, and 104 patients constituted the historical control group treated with rosiglitazone or pioglitazone. At baseline, sitagliptin- and thiazolidinedione-treated patients had identical hemoglobin A1c levels (mean ± SD) (9.4 ± 1.8% and 9.4 ± 1.9%, respectively) and similar known diabetes duration (6.7 ± 5.0 years and 7.6 ± 5.8 years, respectively). Hemoglobin A1c was reduced in both groups at 4 months (P<.001), but the reduction was greater with thiazolidinediones than with sitagliptin (-2.0 ± 1.7% vs -1.3 ± 1.8%; P = .006), as was the proportion of patients achieving a hemoglobin A1c level less than 7.5% (62% vs 46%; P = .026). Of all patients achieving a hemoglobin A1c level less than 7.5% at 4 months, the same proportions in each group sustained their hemoglobin A1c level less than 7.5% by 12 months (59% vs 58%). Sitagliptin was well tolerated.

CONCLUSIONS: Among ethnic minority patients with poorly controlled type 2 diabetes while taking maximum tolerated dosages of metformin and sulfonylureas, third-line add-on therapy with a thiazolidinedione controlled hyperglycemia more effectively than sitagliptin after 4 months.