Blood Test Predicts Rapid Alzheimer’s Decline

Simple Blood Test Flags Risk of Faster Cognitive Decline

A new study reveals that a common blood test can identify individuals with early Alzheimer’s disease who are at a heightened risk of accelerated cognitive decline. The findings, presented at the European Academy of Neurology Congress 2025, highlight a simple metabolic marker for early detection and intervention.

Insulin Resistance as a Predictor

Researchers evaluated 315 non-diabetic patients experiencing cognitive difficulties, including 200 confirmed Alzheimer’s cases. They assessed insulin resistance using the triglyceride-glucose (TyG) index. The study revealed those in the highest third of the TyG index within the mild cognitive impairment (MCI) Alzheimer’s subgroup saw their condition worsen much faster than their peers.

“Once mild cognitive impairment is diagnosed, families always ask how fast it will progress,”

—Dr. Bianca Gumina, Lead Investigator

No such correlation was observed in the non-Alzheimer’s cohort. This suggests a strong link between insulin resistance and the progression of Alzheimer’s disease.

The Role of the TyG Index

The TyG index is a readily available and cost-effective marker of insulin resistance. The study indicates that elevated TyG levels could indicate an individual’s vulnerability to metabolic stress during the prodromal stages of Alzheimer’s. Approximately 6.7 million Americans aged 65 and older are living with Alzheimer’s disease in 2023, according to the Alzheimer’s Association (Alzheimer’s Association).

Implications for Treatment and Research

The study authors, led by Professor Padovani and Professor Pilotto, observed that high TyG levels were also connected to blood-brain barrier disruption and cardiovascular risk factors. However, there was no interaction with the APOE ε4 genotype, indicating that metabolic and genetic risks function via separate pathways.

Identifying high-TyG patients may improve the selection of participants for clinical trials. It could also encourage earlier lifestyle changes or medication to improve insulin sensitivity. Researchers are now exploring how TyG levels correlate with neuroimaging biomarkers for earlier detection and stratification.

“If targeting metabolism can delay progression, we will have a readily modifiable target that works alongside emerging disease-modifying drugs,”

—Dr. Gumina