Abstract

Objectives: To determine the prevalence and compare the characteristics of cognitive impairment assessed using the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE) in patients with type 2 diabetes mellitus (T2DM) aged 40–64 years, and to examine its associations with risk factors and metabolic control.

Methods: A descriptive cross-sectional study was conducted in 99 patients aged 40–64 years with T2DM diagnosed according to the 2024 American Diabetes Association criteria. Participants received outpatient care at the Internal Medicine Clinic, Hue University of Medicine and Pharmacy Hospital, from June 2024 to July 2025. Cognitive function was independently screened using the Vietnamese versions of MoCA and MMSE. Proportions were compared using the chi-square (χ²) test, and discriminatory ability was assessed using receiver operating characteristic (ROC) curve analysis.

Results: MoCA identified cognitive impairment in 42.4% of patients, with a mean score of 23.94 ± 3.26, whereas MMSE identified cognitive impairment in 14.1%, with a mean score of 25.63 ± 2.45. All cases identified by MMSE were classified as mild. Cognitive impairment assessed using MoCA was significantly associated with female sex (p = 0.03), lower educational attainment (primary and lower secondary education compared with upper secondary education, p < 0.001), and higher blood pressure. Mean systolic blood pressure was higher in patients with cognitive impairment than in those with normal cognition (129.52 ± 13.78 vs. 121.58 ± 11.92 mmHg, p = 0.005). ROC analysis showed an area under the curve (AUC) of 0.670 for systolic blood pressure (95% CI: 0.543–0.798, p = 0.015), with a cutoff of 125 mmHg, and an AUC of 0.655 for diastolic blood pressure (95% CI: 0.527–0.783, p = 0.027), with a cutoff of 75 mmHg. No statistically significant associations were observed with time since diabetes diagnosis, body mass index, waist circumference, smoking, alcohol consumption, HbA1c, fasting blood glucose, or lipid levels.

Conclusions: Cognitive impairment was common among middle-aged patients with T2DM aged 40–64 years. MoCA was more sensitive and clinically appropriate than MMSE for screening for early cognitive impairment. Tight blood pressure control plays an important role in preserving brain function in this population.