Associations between triglyceride-glucose-related indices and all-cause and cardiovascular mortality among individuals with atrial fibrillation and metabolic syndrome: a cohort study of the UK biobank.

BACKGROUND: The triglyceride-glucose (TyG) related indices are simple biomarkers of insulin resistance and are associated with metabolic syndrome (MetS) and atrial fibrillation (AF). However, whether TyG-related indices are linked to all-cause and cardiovascular mortality in individuals with coexisting AF and MetS remains unclear. METHODS: We included 2535 participants with both AF and MetS from the UK Biobank. TyG-related indices, including TyG, TyG combined with body mass index (TyG-BMI), TyG combined with waist circumference (TyG-WC), and TyG combined with the waist-to-height ratio (TyG-WHtR), were calculated. The study endpoints were all-cause and cardiovascular mortality. Participants were followed until death or December 31, 2023, whichever occurred first. Associations between TyG-related indices and mortality outcomes were assessed using Cox proportional hazards models and restricted cubic spline (RCS) analyses. RESULTS: Over a mean follow-up period of 12.7 years (IQR: 11.8‒15.2), 956 all-cause deaths and 385 cardiovascular deaths were documented. Kaplan‒Meier survival analyses revealed the highest incidence of all-cause mortality in the fourth quartile of TyG (log-rank P < 0.001). Compared with individuals in the second quartile, individuals in the highest quartile had a significantly increased risk of all-cause mortality (TyG: hazard ratio (HR) 1.36, 95% confidence interval (CI): (1.14‒1.64); TyG-BMI: 1.31, 1.10‒1.56; TyG-WC: 1.41, 1.18‒1.68; TyG-WHtR: 1.56, 1.3‒-1.86). Moreover, TyG, TyG-BMI, and TyG-WHtR were significantly associated with cardiovascular mortality (TyG: HR 1.47, 95% CI 1.10‒1.95; TyG-WC: 1.41, 1.03‒1.93; TyG‒WHtR: 1.35, 1.01‒1.80). RCS analyses revealed nonlinear association between TyG and mortality and between TyG-BMI and all-cause mortality (all P < 0.05). The results of the sensitivity and subgroup analyses were consistent with those of the primary analyses. CONCLUSIONS: This study demonstrateed the prognostic value of TyG-related indices in individuals with AF and MetS. These indices may serve as practical surrogate markers for risk stratification and the prevention of adverse outcomes.