Thirty-nine patients on metformin alone ( age , 647years ; duration of type 2 diabetes mellitus , 7.84.5 years , 27 male , 12 female ; HbA1c , 57.26.9 mmol/mol ; meanSD ) were randomized to receive linagliptin 5mg ( n = 19 ) or glimepiride ( n = 20 ) for a study duration of 12weeks .