C-reactive protein-triglyceride glucose index and all-cause mortality in postmenopausal women: A dual-cohort study from the National Health and Nutrition Examination Survey and the China Health and Retirement Longitudinal Study.

BACKGROUND

Insulin resistance and chronic inflammation each predict cardiovascular mortality, but they are usually studied separately. The C-reactive protein-triglyceride glucose index (CTI) combines both, yet its prognostic value in postmenopausal women, who experience concurrent rises in insulin resistance and inflammation, remains unknown.

METHODS

We identified postmenopausal women from the National Health and Nutrition Examination Survey (NHANES) (1999-2018; n = 7007) and the China Health and Retirement Longitudinal Study (CHARLS) (2011; n = 4235). CTI = 0.412 × ln [hs-CRP (mg/L)] + ln[(fasting triglycerides × fasting glucose)/2]. The endpoint was all-cause mortality. We fitted Cox models, restricted cubic splines (RCS), and piecewise regression with likelihood ratio tests for threshold detection.

RESULTS

Over a median 9.0 years (CHARLS) and 11.9 years (NHANES), 2940 deaths occurred (26.2%). Each 1-unit CTI increase carried a 28% higher mortality hazard after full adjustment (hazard ratio [HR] 1.28; 95% confidence interval [CI] 1.20-1.35; P < 0.001). The dose-response was nonlinear in NHANES (P < 0.001) but linear in CHARLS (P = 0.14). In NHANES, a threshold emerged at CTI = 5.43: above it, per-unit HR = 1.85 (95% CI 1.62-2.11); below, HR = 0.99 (95% CI 0.89-1.10; P = 0.87). The highest versus lowest tertile HRs were 1.51 (1.16-1.97) in CHARLS and 1.35 (1.22-1.49) in NHANES. Excluding baseline cancer cases did not change the results.

CONCLUSION

Higher CTI predicts greater all-cause mortality in postmenopausal women. In the US cohort, risk rose sharply, above CTI = 5.43. The same trend in the Chinese cohort, although linear, suggests that CTI might be a useful risk marker across populations.