Expectation of cutting down of medical bills by administering half-dose sitagliptin

INTERVENTION: Reduction of dose of sitagliptin or not. Standard dose of sitagliptin. CONDITION: Japanese patients with non‐insulin dependent diabetes PRIMARY OUTCOME: HbA1c SECONDARY OUTCOME: Bady weight,1.5AG,C‐peputide index INCLUSION CRITERIA: 1. Age 20 years<= 2. HbA1c <7.0% 3. eGFR 60mL/min/1.73m <= 4. Concomitant medicines is sitagliptin only or sitagliptin and metformin or sitagliptin and sulfonylurea or sitagliptin and metformin and sulfonylurea. 5. Under treatment with fixed diet and exercise. 6. Hb male 13.5‐17.6g/dL female 11.3‐15.2g/dL