title: Sitagliptin Improves the Impaired Acute Insulin Response during a Meal Tolerance Test in Japanese Patients with Type 2 Diabetes Mellitus: A Small-Scale Real-World Study.
abstract: BACKGROUND
  Several studies have shown that dipeptidyl peptidase-4 (DPP-4) inhibitors improve insulin secretion during oral glucose tolerance tests. However, the effects of DPP-4 inhibitors on impaired acute insulin responses in the postprandial state in real-world settings are unknown. Therefore, we evaluated the effects of sitagliptin on the acute insulin responses in Japanese patients with type 2 diabetes mellitus (T2DM) using meal tolerance tests.
  
  
  METHODS
  Twenty-one patients with T2DM were given a test meal (460 kcal), and plasma glucose and insulin were measured at 0, 30, 60, 120, and 180 min after the meal. The insulinogenic index of all of these patients was below 43.2. The postprandial profiles were assessed at baseline and after 3 months of treatment with 50 mg/day sitagliptin after a meal (n = 11) or were untreated (control group; n = 10). This study was a prospective, open-label, non-blinded, non-randomized, clinical study.
  
  
  RESULTS
  Sitagliptin significantly decreased the plasma glucose levels at 60, 120, and 180 min, and significantly increased the plasma insulin levels at 0 and 30 min. There were no significant changes in glucose or insulin in the control group. The insulinogenic index increased significantly in the sitagliptin group compared with the control group (+16.7 vs. +0.1, P < 0.005). However, homeostasis model assessment of insulin resistance and the insulin sensitivity index were not significant different between the two groups.
  
  
  CONCLUSIONS
  Administration of sitagliptin at 50 mg/day after a meal improved the impaired acute insulin response and suppressed postprandial hyperglycemia. Whereas the study is rather small and the design is suboptimal as it is not randomized and not blinded, these results suggest that sitagliptin is effective in Japanese patients with T2DM, many of whom display impaired acute insulin responses after a meal.
authors.affiliation: Division of Cardiovascular Medicine, Endocrinology and Metabolism, Department of Molecular Medicine and Therapeutics, Tottori University Faculty of Medicine, Yonago, Tottori, Japan, ohkura@med.tottori-u.ac.jp.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Ohkura
authors.forename: Youhei
authors.initials: Y
authors.lastname: Fujioka
authors.forename: Keisuke
authors.initials: K
authors.lastname: Sumi
authors.forename: Risa
authors.initials: R
authors.lastname: Nakanishi
authors.forename: Hideki
authors.initials: H
authors.lastname: Shiochi
authors.forename: Naoya
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Matsuzawa
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Izawa
authors.forename: Hiroko
authors.initials: H
authors.lastname: Ohkura
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kato
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Taniguchi
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yamamoto