Different association between triglyceride-glucose index and mild cognitive impairment in type 2 diabetes mellitus patients with and without diabetic kidney disease

Songtao Feng¹Zhen Zhang²Qingyue Gao³Ling Huang²Ya Zhang²Mengting He²Bing Song^4*Wen wen Zhu^5*Li Ding^6*

• ¹Department of Nephrology, Jiangsu University Affiliated People’s Hospital, Jiangsu University, Zhenjiang, China
• ²Department of Endocrinology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, University of Science and Technology of China, Hefei, China
• ³Department of Endocrinology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China; Department of Endocrinology, Anhui Provincial Hospital Affiliated to Bengbu Medical University, Hefei, China, University of Science and Technology of China, Hefei, China
• ⁴Department of Endocrinology, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou Medical University, Jinzhou, China
• ⁵Department of Endocrinology, Huzhou Central Hospital, Affiliated Central Hospital of Huzhou University, Huzhou University, Huzhou, China
• ⁶Department of Endocrinology,Taikang Xianlin Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing University, Nanjing, China

Aim: The triglyceride-glucose (TyG) index, a surrogate marker reflecting metabolic status related to both glucose and lipid homeostasis, has been implicated in the development of diabetes-related complications, including diabetic kidney disease (DKD). Metabolic disturbances in carbohydrate and lipid pathways have also been linked to impairments in cognitive performance. This study aims to explore the association between TyG levels and the presence of mild cognitive impairment (MCI) among individuals with type 2 diabetes mellitus (T2DM), stratified by DKD status. Methods: A total of 243 patients with T2DM were divided into two subgroups based on cognitive status: those with MCI and those without. Clinical parameters were assessed and compared between the two cohorts. The association between TyG index and cognitive function was analyzed. Furthermore, potential predictors of MCI were explored separately in T2DM patients with and without DKD. Results: In individuals with T2DM, those exhibiting MCI (n = 95) showed significantly higher TyG index values in comparison to counterparts with normal cognition (n = 148). Elevated TyG index was linked to reduced performance on the Montreal Cognitive Assessment, a measure of global cognition, as well as diminished scores on both the Verbal Fluency Test and the delayed recall component of the Auditory Verbal Learning Test, which assess executive function and immediate memory, respectively, in patients without DKD. These findings suggest that heightened TyG index may serve as an independent risk indicator for cognitive decline in T2DM individuals without DKD. However, among those with coexisting DKD, no statistically meaningful association between TyG index and cognitive outcomes was observed. Conclusions: Elevated TyG index levels have been linked to an increased likelihood of MCI, particularly affecting executive function and immediate recall, among individuals with T2DM but without DKD.