To assess the efficacy of treatment with sitagliptin or dapagliflozin or lobeglitazone in type 2 diabetes mellitus patients, who had inadequate glycemic control even though use of two drug combination therapy with glimepiride and metformin.

Dual combination therapy with metformin and sulphonylurea is the most commonly used combination regimen to treat patients with type 2 diabetes. But, treatment with the dual combination therapy is often unsuccessful at achieving glycaemic control in patients with type 2 diabetes.

Recently, various oral hypoglycemic agents were developed including dipeptidyl peptidase (DPP)-IV inhibitor, sodium-glucose cotransporter 2 (SGLT2) inhibitor and new peroxisome proliferator-activated receptors (PPARs) agonists.

But, there have been few studies about the glucose lowering effect of these drugs in Type 2 diabetes patients on the dual combination therapy with a sulfonylurea agent and metformin.

Hence, the researchers plan to investigate the efficacy and safety of these drugs in combination with a sulfonylurea agent and metformin in type 2 diabetic patients.

Inclusion Criteria:

• 20 ≤ Age < 80 years
• HbA1c ≥ 7 %
• combination therapy with glimepiride and metformin over 2 months.
• dosage of glimepiride : 1-8mg/day
• dosage of metformin : 500-2550mg/day

Exclusion Criteria:

• Type 1 diabetes, gestational diabetes, or secondary forms of diabetes
• Contraindication to sitagliptin or dapagliflozin or lobeglitazone
• Pregnant or breast feeding women
• Medication which affect glycemic control (ex. steroid)
• Disease which affect efficacy and safety of drugs
• Any major illness (Liver disease, Renal failure, Heart disease, Cancer, etc)
• Not appropriate for oral antidiabetic agent