Abstract
<title>Abstract</title> <p> Background The prevalence of cardiometabolic multimorbidity (CMM) imposes a mounting strain on healthcare systems globally. While the triglyceride-glucose (TyG) index is a recognized surrogate for CMM risk, the utility of the triglyceride-glycated hemoglobin (TyGH) index which incorporates HbA1c remains unexplored. The present investigation was designed to evaluate the relationship between the TyGH index and incident CMM. Methods We drew upon data from the China Health and Retirement Longitudinal Study (CHARLS), a nationally prospective cohort, and included 6,822 participants aged 45 years or older who were followed from 2011 to 2020. Both the TyG and TyGH indices were derived from baseline measurements. Incident CMM was defined as the first emergence of two or more coexisting conditions (diabetes, heart disease, and stroke) over the course of follow-up. A range of analytical tools were applied, including multivariable Cox regression, restricted cubic spline (RCS) modeling, receiver operating characteristic (ROC) curves, and decision curve analysis (DCA). We also performed subgroup analyses to check whether the findings held consistently across different participant subgroups. Results During a median follow-up of 8.43 years, 1,081 participants (15.85%) developed CMM. In models that adjusted for a comprehensive set of confounders, both the TyG index (hazard ratio [HR] 1.40, 95% confidence interval [CI] 1.29–1.52, <italic>p</italic> < 0.001) and the TyGH index (HR 1.43, 95% CI 1.30–1.58, <italic>p</italic> < 0.001) emerged as independent predictors of higher CMM risk. RCS analyses pointed to a non-linear pattern for the TyG-CMM relationship, whereas the TyGH-CMM association appeared to be linear. DCA curves for the two indices were almost completely superimposed, suggesting that their clinical utility is broadly similar. Subgroup analyses did not reveal any meaningful interactions (all <italic>p</italic> for interaction > 0.05). Conclusions An elevated TyGH index exhibits significant independent associations with higher CMM risk, exhibiting clinical utility comparable to the TyG index. The TyGH index offers a practical alternative for CMM risk stratification, with the operational advantage of HbA1c stability. </p>