The TyG Index as a surrogate marker of insulin resistance in Behçet's disease: a case-control study

Behçet's disease is a chronic systemic vasculitis characterized by persistent inflammation and endothelial dysfunction, both of which contribute to metabolic disturbances such as insulin resistance. Insulin resistance and the resulting microvascular impairment may exacerbate tissue injury underlying key dermatologic and ocular manifestations of the disease. The triglyceride-glucose (TyG) index has recently emerged as a practical biomarker of insulin resistance, yet its role in Behçet's disease has not been studied extensively.

To evaluate the ability of the TyG index to differentiate patients with Behçet's disease from healthy controls and to assess its relationship with disease duration and systemic involvement, providing novel insight into metabolic dysregulation in Behçet's disease.

A total of 41 patients with Behçet's disease and 41 age-, sex-, and BMI-matched healthy controls were included. The TyG index was calculated using fasting triglyceride and glucose levels. Receiver operating characteristic (ROC) analysis was conducted to assess diagnostic performance, and subgroup analyses were performed based on disease duration (<10 vs. ≥10 years) and presence of systemic involvement.

The TyG index was significantly higher in BD patients compared to healthy controls (8.57 ± 0.64 vs. 7.72 ± 0.42; p < 0.001). ROC analysis demonstrated high diagnostic accuracy with an AUC of 0.86, and a cutoff value of 7.731 yielded 85% sensitivity and 100% specificity. Among patients with Behçet's disease, those with a disease duration of ≥10 years (n = 20) exhibited significantly higher TyG values (mean 8.95 ± 0.61) compared to those with <10 years of duration (n = 21, mean 8.21 ± 0.54; p = 0.0006). This association was confirmed using the independent samples t-test. Systemic involvement, smoking status, biologic therapy, and pathergy test results showed no significant impact on TyG levels (all p > 0.05).

The TyG index is a promising biomarker for insulin resistance in Behçet's disease and may reflect cumulative inflammatory and metabolic burden that contributes to microvascular tissue injury, including in skin and ocular structures. Its use may aid in identifying patients at elevated cardiometabolic and microvascular risk, particularly those with long-standing disease.