Effect of sitagliptin on blood glucose control in patients with type 2 diabetes mellitus who are treatment naive or poorly responsive to existing antidiabetic drugs: the JAMP study oleh Hiroshi Sakura, Naotake Hashimoto, Kazuo Sasamoto, Hiroshi Ohashi, Sumiko Hasumi, Noriko Ujihara, Tadasu Kasahara, Osamu Tomonaga, Hideo Nunome, Masashi Honda, Yasuhiko Iwamoto, for the JAMP Study Investigators