Association of the C-reactive protein-triglyceride-glucose index with the risk of incident cardiovascular disease in rectal cancer survivors.

Background and objectiveRectal cancer survivors face an elevated cardiovascular disease (CVD) burden shaped by tumor- and treatment-related pathophysiology beyond conventional risk factors. We evaluated the association between the C-reactive protein-triglyceride-glucose index (CTI)-a composite inflammatory-metabolic indicator-and incident CVD in this population.MethodsThis retrospective cohort study enrolled 1,160 rectal cancer survivors from a Chinese tertiary hospital as the discovery cohort and 1,752 from the UK Biobank as an independent validation cohort. Incident CVD was the primary outcome. Multivariable logistic regression, restricted cubic splines, and model performance metrics were used to assess the association, dose-response relationship, and incremental predictive value of CTI.ResultsAfter full multivariable adjustment, each one-SD increment in CTI was associated with an 18% higher risk of incident CVD (OR = 1.18, 95% CI: 1.02-1.36, p = 0.025), with an approximately linear dose-response relationship (p for non-linearity = 0.448) and excess risk concentrated in the highest quartile (Q4 vs. Q1: OR = 1.60, 95% CI: 1.07-2.42, p = 0.024). Adding CTI improved discrimination (AUC = 0.718) beyond the CRP-based model (AUC = 0.713, p = 0.050) and the TyG-based model (AUC = 0.715, p = 0.042), and significantly improved risk reclassification (categorical NRI = 0.052, 95% CI: 0.018-0.086, p = 0.005). The association was stronger in patients aged