DPP4 and Cognitive impairment: In a study conducted on retrospective longitudinal data of 240 older type 2 diabetic patients (drug-naive at baseline) affected by mild cognitive impairment and treated with DPP-4 inhibitor plus metformin (n=120) or sulfonylurea plus metformin (n=120) for two years, it was reported that the DPP-4 administration has a protective role against worsening in cognitive functions [21].