Exploring the Association Between Cognitive Decline and Triglyceride‐Glucose Index: A Systematic Review and Meta‐Analysis

ABSTRACT Background Cognitive decline and dementia are debilitating conditions that compromise the quality of life and charge the healthcare system with a substantial socioeconomic burden. In this context, emerging evidence supports an association between the triglyceride‐glucose index (TyG), a surrogate insulin resistance marker, and cognitive decline and dementia. Hence, we systematically reviewed the studies assessing the TyG index in patients with cognitive decline and their controls. Methods Online international databases (PubMed, Scopus, Embase, and the Web of Science) were searched comprehensively for studies showing the TyG index in patients with cognitive decline/impairment. Random‐effect meta‐analyses were conducted to calculate the standardized mean difference (SMD), pooled odds ratio (OR), and pooled area under the curve (AUC), in addition to 95% confidence intervals (CIs) for the comparisons of groups. Results Seventeen studies were included in our analysis. Then, we conducted a meta‐analysis, demonstrating that patients with cognitive decline had significantly higher levels of TyG index than those without (SMD 0.83, 95% CI 0.16 to 1.50, p = 0.015). Moreover, our data showed that a 1‐unit increase in the TyG index was associated with higher odds of cognitive decline (adjusted OR [aOR] 2.86, 95% CI 1.49 to 5.50, p = 0.002). Further, we observed that patients in the fourth TyG quartile with higher values of the TyG index than the first quartile presented with more increased cognitive decline (aOR 1.62, 95%CI 1.11 to 2.38, p = 0.013). Finally, pooled AUC data for the diagnostic performance of the TyG index resulted in an overall AUC value of 0.73 (95% CI 0.66 to 0.79). Sensitivity and specificity were also calculated as 0.695 and 0.687, respectively. Conclusion This study supports the clinical utility of the TyG index in patients with cognitive decline and solicits more focused studies to consolidate its usage in clinical settings and real‐world practice. The role of insulin resistance and triglyceride‐glucose index (TyG) has been investigated in cognitive decline and dementia. Based on 17 included studies, patients with cognitive decline had significantly higher levels of TyG index compared to controls. TyG, as a surrogate marker of insulin resistance, could be a potentially useful biomarker in dementia and cognitive decline.