C-Reactive Protein-Triglyceride-Glucose Index, Inflammatory-Metabolic Burden, and Prevalent Stroke in U.S. Adults: NHANES 1999-2010

Background The C-reactive protein-triglyceride-glucose index (CTI) integrates inflammatory and metabolic markers, but recent studies have already linked CTI to stroke and cardiovascular outcomes. Whether CTI provides information beyond established risk factors in the U.S. general population remains uncertain. Methods We analyzed 11,809 adults from NHANES 1999-2010 with fasting laboratory, stroke, covariate, and survey-design data. Stroke was defined by self-reported physician diagnosis. Survey-weighted logistic regression estimated odds ratios (ORs) and 95% confidence intervals (CIs). We evaluated restricted cubic splines, exploratory subgroup interactions, and sensitivity to excluding CRP >10 mg/L. CTI was compared with TyG and its component biomarkers, and incremental value was quantified using weighted C-statistics, integrated discrimination improvement, and continuous net reclassification improvement. Results Among 11,809 participants, 411 reported stroke. CTI was associated with prevalent stroke before cardiometabolic adjustment (unadjusted OR = 2.05, 95% CI: 1.74-2.42; demographically adjusted OR = 1.57, 95% CI: 1.31-1.89; both P < 0.001), but the fully adjusted association was attenuated (OR = 1.22, 95% CI: 0.98-1.53; P = 0.080). There was no evidence of non-linearity, and subgroup interaction tests, including the CTI-by-age interaction, were not statistically significant. Adding CTI to traditional covariates minimally changed discrimination (weighted C-statistic, 0.846 to 0.847). Conclusions CTI reflects an inflammatory-metabolic burden phenotype, but its association with prevalent stroke was largely accounted for by traditional risk factors, and it provided negligible incremental discrimination in this cross-sectional analysis.