Associations between the C-reactive protein-triglyceride-glucose index and its derived indices and the incidence and progression of cardiometabolic multimorbidity in participants with metabolic dysfunction-associated steatotic liver disease: a large-scale prospective cohort study

BACKGROUND: The C-reactive protein-triglyceride-glucose index (CTI), a composite biomarker reflecting insulin resistance and systemic inflammation, has been linked to metabolic dysfunction-associated steatotic liver disease (MASLD) and cardiometabolic diseases (CMDs). However, the role of CTI and its obesity-related derivatives in cardiometabolic multimorbidity (CMM) development and progression among MASLD patients remains unclear. The study evaluated associations of CTI-related indices with the incidence and progression of CMM, assessed their incremental predictive value, and explored potential biomarkers. METHODS: This cohort study included 109,181 UK Biobank participants with MASLD and without CMDs at baseline. CMM was defined as the coexistence of ≥ 2 CMDs, including type 2 diabetes mellitus (T2DM), ischemic heart disease (IHD), and stroke. Four CTI-related indices were calculated: CTI, CTI-body mass index (CTI-BMI), CTI-waist circumference (CTI-WC), and CTI-waist-to-height ratio (CTI-WHtR). Associations with CMM incidence and progression were analyzed using traditional Cox and multistate models. Predictive performance was assessed using the C-index, net reclassification improvement (NRI), and integrated discrimination improvement (IDI). Exploratory mediation analyses were conducted to examine whether metabolic, inflammatory, hepatic, and renal biomarkers statistically accounted for part of the associations. RESULTS: Over a median follow-up of 16 years, 4,219 participants developed CMM. All four indices were positively associated with incident CMM, with CTI-WHtR and CTI-WC showing more pronounced associations. Hazard ratios (HRs) (95% confidence interval) per 1-SD increase were 1.62 (1.58-1.66) for CTI-WHtR, 1.57 (1.53-1.61) for CTI-WC, 1.53 (1.49-1.57) for CTI-BMI, and 1.50 (1.45-1.54) for CTI (all P < 0.001). Multistate analyses indicated consistent positive associations with transitions from baseline to first CMD (FCMD) (HRs: 1.41-1.53), FCMD to CMM (HRs: 1.17-1.24), and CMM to death (HRs: 1.07-1.21), particularly for CTI-WHtR and CTI-WC. Subtype-specific analyses confirmed their pronounced associations, notably for T2DM incidence and IHD-to-CMM progression. Adding CTI-related indices to the conventional model resulted in modest but statistically significant improvements in predictive performance, with CTI-WC and CTI-WHtR showing the greatest improvements in the C-index, NRI, and IDI. Biomarkers of glycemic dysregulation, lipid metabolism, systemic inflammation, and organ dysfunction may partly account for the associations between CTI indices and incident CMM. CONCLUSION: CTI-related indices, particularly CTI-WHtR and CTI-WC, were significantly associated with the incidence and progression of CMM in individuals with MASLD. These indices provided modest incremental predictive value and may serve as complementary markers for risk stratification. Further external validation and clinical utility assessment are needed before their routine use in clinical practice.