Adding Sitagliptin or Pioglitazone to Type 2 Diabetes Mellitus Insufficiently Controlled With Metformin and Sulfonylurea (JAS)

• Mean Change in Glycosylated Hemoglobin (A1C) [ Time Frame: 24 weeks ] [ Designated as safety issue: Yes ]
  A1C change from baseline to 24 weeks
  
  
• Baseline A1C [ Time Frame: Baseline ] [ Designated as safety issue: No ]
  baseline A1C
  
  
• The Percentages of Patient Achieving an A1C <7% [ Time Frame: 24 weeks ] [ Designated as safety issue: No ]
  The percentages of patient achieving an A1C <7% at endpoint
  
  

• Changes in Fasting Plasma Glucose [ Time Frame: 24 weeks ] [ Designated as safety issue: Yes ]
  fasting serum sugar change from baseline to 24 weeks
  
  
• Changes in High Sensitive C-reactive Protein [ Time Frame: 24 weeks ] [ Designated as safety issue: No ]
  fasting high sensitive serum C-reactive protein change from baseline to 24 weeks
  
  
• Changes in Homoeostasis Model Assessment of Insulin Resistance (HOMA-IR) [ Time Frame: 24 weeks ] [ Designated as safety issue: No ]
  HOMA-IR change from baseline to 24 weeks
  
  
• Body Weight Change [ Time Frame: 24 weeks ] [ Designated as safety issue: Yes ]
  body weight change from baseline to 24 weeks
  
  
• Percentages of Patients With Total Adverse Events (AE) [ Time Frame: 24 weeks ] [ Designated as safety issue: Yes ]
  percentages of total adverse events
  
  
• Change in Fasting Total-cholesterol [ Time Frame: 24 weeks ] [ Designated as safety issue: No ]
  Total-cholesterol change from baseline to 24 weeks
  
  
• Change in Fasting Low-density Lipoprotein Cholesterol (LDL-C) [ Time Frame: 24 weeks ] [ Designated as safety issue: No ]
  LDL-C change from baseline to 24 weeks
  
  
• Change in Fasting Triglycerides(TG) [ Time Frame: 24 weeks ] [ Designated as safety issue: No ]
  TG change from baseline to 24 weeks
  
  
• Change in Fasting High-density Lipoprotein Cholesterol(HDL-C) [ Time Frame: 24 weeks ] [ Designated as safety issue: No ]
  HDL-C change from baseline to 24 weeks
  
  
• Change in Fasting Plasma Alanine-aminotransferase (ALT) [ Time Frame: 24 weeks ] [ Designated as safety issue: Yes ]
  ALT change from baseline to 24 weeks
  
  
• Percentages of Patients With Mild to Moderate Hypoglycemia [ Time Frame: 24 weeks ] [ Designated as safety issue: Yes ]
  Incidence of mild to moderate hypoglycemia after treatment
  
  
• Percentages of Patients With Edema [ Time Frame: 24 weeks ] [ Designated as safety issue: Yes ]
  proportion of edema after treatment
  
  
• Percentages of Patients With Gastrointestinal Adverse Events [ Time Frame: 24 weeks ] [ Designated as safety issue: Yes ]
  Proportion of Gastrointestinal adverse events after treatment
  
  
• Percentages of Patients With Nasopharyngitis [ Time Frame: 24 weeks ] [ Designated as safety issue: Yes ]
  Proportion of Nasopharyngitis after treatment
  
  
• Percentages of Patients With Severe Hypoglycemia [ Time Frame: 24 weeks ] [ Designated as safety issue: Yes ]
  Proportion of severe hypoglycemia after treatment
  
  
• Baseline Fasting Plasma Glucose [ Time Frame: baseline ] [ Designated as safety issue: No ]
  Baseline fasting plasma glucose
  
  
• Baseline High Sensitive C-reactive Protein [ Time Frame: baseline ] [ Designated as safety issue: No ]
  Baseline high sensitive C-reactive Protein
  
  
• Baseline Homoeostasis Model Assessment of Insulin Resistance (HOMA-IR) [ Time Frame: Baseline HOMA-IR ] [ Designated as safety issue: No ]
  Baseline HOMA-IR
  
  
• Baseline Alanine-aminotransferase (ALT) [ Time Frame: Baseline ] [ Designated as safety issue: Yes ]
  Baseline alanine-aminotransferase
  
  
• Baseline Body Weight [ Time Frame: Baseline ] [ Designated as safety issue: Yes ]
  Baseline body weight
  
  
• Baseline Total Cholesterol [ Time Frame: Baseline ] [ Designated as safety issue: No ]
  Baseline Total cholesterol
  
  
• Baseline Triglyceride (TG) [ Time Frame: Baseline ] [ Designated as safety issue: No ]
  Baseline TG
  
  
• Baseline Low-density Lipoprotein Cholesterol (LDL-C) [ Time Frame: Baseline ] [ Designated as safety issue: No ]
  Baseline LDL-C
  
  
• Baseline High-density Lipoprotein Cholesterol (HDL-C) [ Time Frame: Baseline ] [ Designated as safety issue: No ]
  Baseline HDL-C
  
  

This is a prospective, open-label, randomized, parallel, 24-week study. Inclusion criteria: type 2 diabetes patients who were treated with stable doses of sulfonylurea and metformin to their half maximally dose (sulfonylureas > half maximal dose, and metformin > 1500 mg/d) for > 10 weeks. > 20 years old; A1C:> 7.0 % and < 11% Exclusion criteria: insulin use within 12 weeks of the screening visit, any contraindications for use of sitagliptin or pioglitazone, impaired renal function (serum creatinine > 1.4 mg/dl), alanine aminotransferase (ALT) or aspartate aminotransferase levels (AST) > 2.5 times the upper limit of normal (ULN), current or prepare to pregnancy and lactation.

Primary Purpose:

compare the change in hemoglobin A1c and the proportion of patients achieving A1C < 7% between the 2 groups

Secondary Purposes:

1. Changes in fasting plasma glucose, high sensitive C-reactive protein (hsCRP)
2. Homeostasis model assessment-β cell function(HOMA-β) will be calculated to assess changes in β-cell function and HOMA-insulin resistance(HOMA-IR)to assess changes in insulin resistance
3. Body weight change, proportion of side effects