A 48 year old male with a 8 year history of type 2 diabetes…

A 48 year old male with a 8 year history of type 2 diabetes presents to your office for follow up. He has a BMI of 32.  His A1c is 8.2% despite metformin 1gm BID and has a history of of CKD stage 1.  No weight gain, excessive thirst, or polyuria.  He has a personal history HTN and dyslipidemia. What medication class is a best choice for add-on therapy per ADA guidelines?