Investigation of the relationship between the triglyceride-glucose index and metabolic and hematological parameters in obese individuals

Abstract

Background/aim: This research examined the association between the triglyceride-glucose (TyG) index and metabolic, hepatic, and hematologic variables in a population of severely obese subjects, with a focus on the assessment of glycemic control. Materials and methods: This retrospective study included 315 adult patients with a body mass index (BMI) ≥ 35 kg/m² who were evaluated for bariatric surgery. Participants were grouped according to HbA1c levels: those with HbA1c ≥ 6.5% and those with HbA1c < 6.5%. TyG, atherogenic index of plasma (AIP), fibrosis-4 (FIB-4), aspartate aminotransferase-to-platelet ratio index (APRI), and hematological inflammation markers were assessed and compared between groups. To investigate associations, correlation and regression analyses were conducted. Results: Individuals with HbA1c ≥ 6.5% had significantly higher TyG, AIP, APRI, and FIB-4 values than those with lower HbA1c. The TyG index showed a strong correlation with both HbA1c (r = 0.403, p < 0.001) and AIP (r = 0.866, p < 0.001), and was identified as an independent predictor of HbA1c, explaining 20.5% of its variance. Moderate correlations were also found between liver fibrosis scores and systemic inflammatory indices. No significant differences were observed in hematologic markers across HbA1c groups, suggesting a closer link between inflammation and obesity rather than glycemic status. Conclusion: The TyG index may serve as a practical and accessible marker for metabolic risk and glycemic control in obese individuals. Its integration with other noninvasive indices like AIP, APRI, and FIB-4 may support a more comprehensive evaluation of cardiometabolic and hepatic risk profiles in clinical settings.