Associations of different insulin resistance-related indices with the incidence and progression trajectory of cardiometabolic multimorbidity: a prospective cohort study from UK biobank

Despite established associations between insulin resistance (IR)-related indices and cardiometabolic diseases (CMDs), most studies are limited to single CMD outcomes. The study aimed to examine the influence of IR-related indices on the incidence, predictive value, and progression trajectory of cardiometabolic multimorbidity (CMM), as well as potential biological mechanisms.

This prospective study included 374,274 individuals from the UK Biobank who were free of CMDs at baseline. CMM was defined as the presence of two or more CMDs, including type 2 diabetes (T2D), coronary heart disease (CHD), and stroke. Five indices were developed to assess IR levels: triglyceride-glucose (TyG) index, TyG-body mass index (TyG-BMI), TyG-waist circumference (TyG-WC), TyG-waist-height ratio (TyG-WHtR), and triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio. Cox proportional hazards and multi-state models were utilized to examine the associations between IR-related indices and CMM incidence and transition, respectively, with results expressed as hazard ratios (HRs) and 95% confidence intervals (CIs). The predictive utility of these indices was assessed using the net reclassification index (NRI) and integrated discrimination improvement index (IDI). Mediation analyses were conducted to quantify the potential mediating roles of biomarkers.