Many studies have examined the correlation between metabolic disorders and cardiovascular diseases with a particular focus on obesity and its impact on outcomes. Recently, the triglyceride-glucose (TyG) index, an indicator of insulin resistance, was calculated using the log (fasting triglycerides [mg/dL] × fasting glucose [mg/dL]/22). Studies have suggested that the TyG index may serve as an accurate predictor of cardiovascular risk in non-diabetic individuals (11, 12).
In 2020, a study examined the connection between TyG index scores and the risk of coronary heart disease, congestive heart failure (CHF), stroke, and hypertension among non-diabetic individuals. This investigation comprised 20 cohort studies with 1,797,630 participants. The results revealed that higher TyG index values were associated with increased risks of CHD, CHF, stroke, and hypertension. Therefore, further research is necessary to establish causal links between TyG index and cardiovascular diseases (13).
Our research found that when age, sex, race, BMI, and other factors were considered, an increase in the TyG index was associated with a higher risk of developing coronary heart disease. However, after conducting sensitivity and specificity tests, we determined that TyG was not a reliable indicator for all the variables we studied. Therefore, while TyG may be a useful tool for identifying individuals at a higher risk of cardiovascular disease in the general population, it should not be used as an independent predictor.
Current evidence suggests that TyG is an effective and reliable indicator of insulin resistance, as demonstrated by a Mexican study (14), which demonstrated its high sensitivity (96.5%) and specificity (85.0%) compared with gold standard tests, such as the HIEG clamp test (15). The TyG index has proven to be a superior predictor compared with the once-revered HIEG clamp test (16), which is both expensive and time-consuming (17). TyG has outperformed other assessments of insulin resistance, such as homeostasis model assessment-insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), and TG/HDL-C ratio, in terms of both accuracy and cost efficiency (18, 19). Triglycerides and glucose are readily available across hospital systems, allowing this test to provide cost savings to both patients and providers (20).
Vega et al. (2013) conducted a prospective study to explore the association between TyG and cardiovascular disease (CVD), specifically cardiovascular dementia. Initial research explored the relationship between the TyG index and mortality due to cardiovascular causes in 39,447 men, concluding that it did not predict CVD mortality; however, this research was limited by gender selection (21). Another study involving 5,014 healthy individuals demonstrated that higher TyG index scores were significantly associated with an increased risk of CVD (22). They developed a new model incorporating both the TyG index and Framingham variables for greater predictive effectiveness in the risk of CVD development in healthy individuals but only tested it against these individuals in their study. Therefore, understanding the prognostic role of the TyG index in patients with coronary artery disease (CAD) could be extremely valuable (8).
The exact relationship between the TyG index and cardiovascular disease (CVD) remains unclear (23, 24). Given that its formula contains both triglycerides and glucose, recent studies have identified them as potential causal agents of CVD (25). In addition, HTG increased LDL particle formation. Fourteen Studies have also shown that plasma triglycerides in the high normal range may serve as an early indicator of cardiovascular events related to glucose disorders. Gaining control of plasma triglycerides through weight loss or drugs often helps to improve glycemic control (26, 27). Genetic polymorphisms affecting triglyceride metabolism may also be linked to higher fasting plasma glucose levels (28). High carbohydrate intake, which might increase plasma triglycerides and glucose, was associated with greater risks of total mortality, as demonstrated in The Prospective Urban Rural Epidemiology (PURE) Study (29). The TyG index can also serve as a useful indicator for metabolic disorder identification (30, 31); However, inflammatory markers such as tumor necrosis factor-a, interleukins, leukocytes, and fibrinogen are more predictive of metabolic syndrome and related disorders (32, 33), TyG index may serve better when used specifically to assess cardiometabolic risk estimation.
The potential implications for clinical practice are substantial, and this information could be harnessed to develop more accurate screening tools or even to guide lifestyle interventions that might prevent the onset of debilitating conditions concurrently. Overall, this research represents an encouraging advancement in our understanding of cardiovascular health beyond conventional markers such as blood pressure or cholesterol levels.
This study has some limitations, including the fact that it is cross-sectional, which means that a causal relationship cannot be established. Additionally, the data collected were based on self-reports, which may be subject to recall bias, especially in the older population. However, this study is representative of the American population, and although it cannot be generalized to all populations and age groups, it remains valuable. Future studies should be conducted in different populations, ethnicities, and age groups to further understand this topic.