Study protocol. After an outpatient observation period of 1 month or longer, patients were randomized to the V/S group which initially received vildagliptin (50 mg twice daily) or the S/V group which initially received sitagliptin (50 mg once daily). The drugs were then switched so that the V/S group received sitagliptin and the S/V group received vildagliptin. ↑ indicates continuous glucose monitoring (CGM) on the second and third hospital days. Identical meals were given to all patients during hospitalization.