Association between triglyceride-glucose related indices and all-cause and cardiovascular mortality among the population with cardiovascular-kidney-metabolic syndrome stage 0–3: a cohort study

Cardiovascular-Kidney-Metabolic (CKM) syndrome typically commences with the interaction of insulin resistance (IR), excessive or dysfunctional obesity, and the consequent systemic inflammatory response and oxidative stress. The relationship between the triglyceride-glucose (TyG) index and TyG-related indices that may simply assess IR and obesity, as well as the mortality risk in the CKM syndrome population, remains ambiguous. This study included 6,383 participants from the National Health and Nutrition Examination Survey (NHANES) 2009–2018. The TyG index, TyG-waist-to-height ratio (TyG-WHtR), TyG-waist circumference (TyG-WC), and TyG-body mass index (TyG-BMI) were developed. Cox proportional hazards models, smooth curve fitting, and two-stage Cox proportional hazards models were employed to examine the association of TyG and TyG-related indices with all-cause and cardiovascular mortality in the CKM syndrome population. Subgroup analyses and interaction tests were conducted to evaluate the risk within various demographics. In survey-weighted multifactorial regression analyses, a significant positive association existed between TyG, TyG-related indices, and both all-cause mortality and cardiovascular mortality, except for the TyG index, which did not demonstrate a significant link with all-cause mortality. Of these indices, the TyG-WC index exhibited the strongest correlation with all-cause mortality, with a hazard ratio (HR) of 1.50 and a 95% confidence interval (CI) of 1.18–1.92, followed by the TyG-WHtR index (HR: 1.45, 95%CI 1.13–1.85). The TyG-WHtR index demonstrated the strongest correlation with cardiovascular mortality (HR: 1.85, 95% CI 1.19–2.86), followed by the TyG-WC index(HR: 1.83, 95%CI 1.21–2.78). An L-shaped association was identified between TyG-WHtR, TyG-BMI, and all-cause mortality in CKM syndrome during the examination of nonlinear relationships (both P for log-likelihood ratio < 0.05). The TyG-WHtR, TyG-WC, and TyG-BMI indices exhibited a more pronounced correlation with all-cause mortality in those with CKM syndrome stages 1 and 3 (P value < 0.05, P for interaction < 0.05). Our study emphasizes the association between TyG and TyG-related indices and mortality in individuals with CKM syndrome stages 0–3. Individuals with CKM syndrome stages 1 and 3 should be more vigilant to abnormal alterations in TyG-related indices.