A large amount of evidence indicates that diabetes (DM) is related to mild cognitive impairment (MCI), vascular dementia and Alzheimer disease (AD). Biological, clinical and epidemiological data all support the close link between diabetes and Alzheimer disease. AD and type 2 diabetes (T2DM) have common pathological features, including inflammation, changes in insulin signaling, or vascular damage. Event-related potential (ERP) is a specific stimulus that acts on the sensory system or a certain part of the brain. When the stimulation is given or withdrawn, the potential change in the brain area is caused. It is suitable for the assessment of brain dysfunction, especially for the assessment of people with early subclinical disease states. Among them, P300 belongs to a kind of ERP, which is an endogenous special evoked potential related to cognitive function. It can identify and evaluate early changes in cognitive function. Therefore, it can be recognized in clinical neurological or psychiatric diseases. The change of cognitive function provides reliable objective indicators, which is of great significance for early drug intervention and treatment and improving the long-term quality of life of patients. Studies have found that anti-diabetic drugs can improve cognitive and memory impairment, and have a positive effect on mitochondrial and synaptic function, neuroinflammation and brain metabolism. Anti-diabetic drugs can be developed as the treatment of MCI and AD diseases in diabetic and non-diabetic patients. Both basic and clinical trials have evidence that metformin has considerable potential for the treatment of cognitive dysfunction in T2DM. Basic experiments have confirmed that SGLT-2 inhibitors may improve the pathological state of AD, but the clinical evidence is still unclear. As the representative drug of SGLT-2, dapagliflozin, as the intervention drug in this study, focuses on its effect on improving the cognitive function of diabetic patients, and compares its effectiveness in improving cognitive function with metformin.

This study is a randomized controlled, single-center study of the cognitive function of diabetic patients in the Department of Endocrinology in our hospital. Through the collection of clinical data during the outpatient or hospitalization period, as well as the clinical data of follow-up at different times in the later period, the conclusion is drawn after statistical analysis. For the population who passed the observational study in the first part, patients who meet the conditions of intervention will be further screened to enter the intervention study in the second part. Patients with type 2 diabetes who meet the enrollment criteria and enter the second part are randomly divided into 3 groups according to 1:1:1;1.Lifestyle intervention group; 2. Metformin treatment group; 3. Dapagliflozin treatment group; There are four groups with healthy control (no intervention). Follow-up review and blood samples were taken after 12 weeks respectively. After the first follow-up, follow-up can be extended to 24 weeks depending on the patient's wishes. Combined with the number of patients with diabetes in endocrinology department of our hospital in the past, and considering the nature of this study and other factors, 90 patients with type 2 diabetes and 30 healthy controls were included for research and analysis.