Simple Insulin Resistance Test as a Predictor of Cognitive Decline in Alzheimer's Patients

Recent research presented at the European Academy of Neurology (EAN) Congress 2025 suggests that a routine blood test measuring insulin resistance through the triglyceride-glucose (TyG) index may serve as a valuable tool in predicting the progression of cognitive decline in individuals with early Alzheimer's disease. The study, conducted by neurologists at the University of Brescia, analyzed data from 315 non-diabetic patients with cognitive impairments, including 200 with confirmed Alzheimer's disease, over a three-year follow-up period.

The TyG index, a low-cost and routinely available marker, was used to assess insulin resistance levels in participants. Findings revealed that patients in the top third of the TyG index within the mild cognitive impairment (MCI) and Alzheimer's spectrum experienced a significantly faster decline in cognitive function, losing more than 2.5 points annually on the Mini Mental State Examination (MMSE). Specifically, these patients had a hazard ratio of 4.08 for rapid deterioration compared to those with lower TyG levels. Interestingly, this association was not observed in patients with other neurodegenerative diseases, indicating a disease-specific vulnerability.

Insulin resistance has been linked to Alzheimer’s disease mechanisms such as impaired neuronal glucose uptake, increased amyloid accumulation, disruption of the blood-brain barrier, and neuroinflammation. The study also found that a higher TyG was associated with blood-brain barrier disruption and cardiovascular risk factors, although it did not interact with the APOE ε4 genetic marker, suggesting that metabolic and genetic risks may influence disease progression through separate pathways.

Lead researcher Dr. Bianca Gumina emphasized the clinical relevance, stating that identifying insulin resistance via the TyG index could help target early interventions and improve patient stratification in clinical trials for anti-amyloid or anti-tau therapies. The research highlights the potential to incorporate a simple, cost-effective test into routine clinical practice to better predict disease trajectory and implement timely lifestyle and pharmacological interventions.

Overall, this study underscores the importance of metabolic health in Alzheimer's progression and offers new avenues for personalized treatment strategies aimed at delaying cognitive decline.