A higher C-reactive protein/triglyceride-glucose index is associated with all-cause mortality among middle-aged and older Chinese adults

The C-reactive protein/triglyceride-glucose index (CTI) integrates inflammatory and insulin-resistance-related metabolic information, but the dose–response shape and robustness of its association with mortality remain uncertain. We analysed 11,221 adults aged ≥ 45 years from the China Health and Retirement Longitudinal Study, with mortality follow-up through 2020. Because proportional-hazards diagnostics indicated time dependence, the Cox estimate represented an average hazard ratio over follow-up. During a median follow-up of 8.4 years, 1,133 deaths occurred. Each empirical interquartile-range increase in CTI was associated with a higher average hazard of all-cause mortality after adjustment (hazard ratio 1.48, 95% confidence interval 1.37–1.60); the highest versus lowest quartile hazard ratio was 2.05 (1.72–2.45; P for trend < 0.001). The approximately linear association remained positive after excluding participants with C-reactive protein > 10 mg/L or deaths within two years and among complete cases. The association appeared stronger during the first five years, although the CTI-by-time interaction was not statistically significant. In exploratory internal analyses, adding CTI modestly increased apparent discrimination (C-index, 0.785 to 0.793; 5-year area under the curve, 0.795 to 0.803). CTI summarizes inflammatory and metabolic information associated with mortality, although its modest apparent incremental prognostic contribution requires external validation.