Objective:To investigate the effect of dapagliflozin on cognitive function in middle-aged and elderly type 2 diabetes mellitus patients and related factors.Methods:This was a retrospective study. A total of 200 patients who were hospitalized in the Department of Endocrinology, the Second Affiliated Hospital of Anhui Medical University from August 2021 to August 2022 were recruited randomly. They were divided into the dapagliflozin group and control group. Clinical data were collected; plasma levels of β-amyloid protein(Aβ) 40 and Aβ42 were measured. The Montreal cognitive assessment(MoCA) and the mini-mental state examination(MMSE) were employed to assess cognitive function in both groups. Based on MoCA scores, patients in the dapagliflozin group were further categorized into mild cognitive impairment(MCI) and non-MCI subgroups. Differences among groups were analyzed and compared using t-test, χ2 test, and Mann-Whitney U test, and multivariable logistic regression was used to identify relevant factors associated with cognitive impairment in diabetes patients. Results:Compared to the control group, the dapagliflozin group exhibited significant increases in MMSE and MoCA scores, estimated glomerular filtration rate, and plasma concentration Aβ40(all P<0.05); And the incidence of MCI, homeostasis model assessment for insulin resistance(HOMA-IR), total cholesterol, triglycerides, urine albumin creatine ratio, plasma Aβ42, and Aβ42/Aβ40 ratio were significantly decreased(all P<0.05). Compared with the MCI subgroup, duration of dapagliflozin treatment in the non-MCI subgroup were significantly increased( P<0.05); There were statistically significant decreased in the non-MCI subgroup in age, systolic blood pressure, fasting plasma C-peptide, and HOMA-IR(all P<0.05). Multivariable logistic regression analysis showed that duration of dapagliflozin treatment was a protective factor for cognitive dysfunction( OR=0.322, 95% CI 0.150-0.692, P=0.004) and the age and HOMA-IR were risk factors( OR=1.109, 95% CI 1.014-1.212, P=0.023; OR=3.376, 95% CI 1.276-8.931, P=0.014). Conclusion:Dapagliflozin may improve cognitive function and significantly reduce the incidence of MCI in middle-aged and elderly patients with type 2 diabetes mellitus, possibly associated with the improvement of insulin resistance.