We used the HGI to test the hypothesis that the change in HbA1c associated with the TyG index in a non-diabetic adult population are indices are highly reliable in assessing IR and glucose metabolism and may be markers of risk independent of FPG and the other variables assessed in this study.
Since 2010 the American Diabetes Association has approved HbA1c for the diagnosis of diabetes and the detection of pre-diabetes (13). The HGI calculates fluctuation of HbA1c as a function of variables other than just the blood glucose concentration (14). Advanced glycation end products (AGEs) lead to IR, and increased HGI is associated with elevated levels of AGEs (15). A study has shown that there is less insulin sensitivity in subjects with high HGI when compared to subjects with normal or low HGI regardless of BMI, sex, or age (16). Furthermore, studies including non-diabetic individuals who had elevated HGI were at increased risk for atherosclerosis, coronary heart disease, and chronic kidney disease (17–19), and the ACCORD study (6) demonstrated that HGI could predict cardiovascular risk. Our study showed a statistically significant correlation of the association between the elevation of HGI and HOMA-IR.
The TyG index is a commonly used substitute indicator for evaluate IR being considered very reliable (20). Its usefulness as an easily measurable marker for both metabolic syndrome and the IR has been established by early research carried out by Abbasi et al. and Simental-Mendía et al. (21, 22), and its computation entails only basic laboratory parameters such as glucose and triglycerides. Moreover, as compared to surrogate markers such as HOMA-IR, the TyG index has been found to be more effective in anticipating IR, when matched with a direct measurement method like the hyperglycemic clamp method (23). However, a recent systematic review found evidence of moderate to low quality concerning the TyG marker's effectiveness as a surrogate biomarker for IR diagnosis due to the variation among studies, considering additional validation and standardized cut-off values are necessary to employ this marker in clinical practice (24). Despite the cited systematic review and in agreement with several published manuscripts, our study found a statistically significant result of the association between elevations of TyG with elevation of HOMA-IR.
Our study on the HGI, TYG index and its relation to IR showed a significant association between these three parameters in the analyzed sample. This suggests that both indices are highly reliable in measuring IR and glucose metabolism, and both can be used interchangeably in clinical practice. Furthermore, the study findings provide valuable insights into the pathophysiology of metabolic disorders such as diabetes, obesity, and cardiovascular diseases, where IR is a central feature. This study supports the notion that the HGI and TyG index are reliable indicators for IR diagnosis, and its use can facilitate the early identification of individuals at risk of developing metabolic disorders. Therefore, the findings of this study have significant implications for clinical practice, public health, and research in the field of metabolic disorders.