Association of C-reactive protein-triglycerides-glucose index-waist to height ratio and cardiometabolic multimorbidity in middle-aged and older adults: a nationwide cohort study.

BACKGROUND

Cardiometabolic multimorbidity (CMM) poses a severe global health burden. Effective prediction requires biomarkers capturing its complex pathophysiology, integrating inflammation, insulin resistance (IR), and central obesity. The C-reactive protein-triglycerides-glucose index-waist to height ratio (CTI-WHtR) is a composite index synthesizing these three pathways, but its longitudinal association with CMM risk remains unestablished.

METHODS

This prospective analysis utilized data from the China Health and Retirement Longitudinal Study (CHARLS). Cohort 1 (n = 8,875), free of CMM at baseline (2011), was established to assess the association between baseline CTI-WHtR and incident CMM. Cohort 2 (n = 5,807), a sub-cohort of longitudinal analysis, was analyzed to evaluate the impact of cumulative CTI-WHtR (cuCTI-WHtR) exposure (up to 2015) on CMM risk. The primary outcome was new-onset CMM (≥ 2 of diabetes, heart disease, or stroke). Cox proportional hazards models, restricted cubic splines, threshold analysis, and ROC curves were employed.

RESULTS

During the follow-up period, 873 and 490 incident CMM cases occurred in Cohort 1 and Cohort 2, respectively. After multiple adjustment, participants in the highest quartile of baseline CTI-WHtR had a 2.85-fold (95% CI 2.26–3.58) higher CMM risk compared to the lowest quartile (P < 0.001). A similar dose–response relationship was observed for cuCTI-WHtR (Q4 HR = 2.76, 95% CI 2.04–3.75). RCS analysis revealed a non-linear association with a significant inflection point. Both baseline and cumulative CTI-WHtR demonstrated superior predictive performance for CMM compared to its individual components (CTI or WHtR). Results remained robust across multiple sensitivity analyses.

CONCLUSION

Both baseline and cumulative CTI-WHtR are strong, independent, and non-linear predictors of new-onset CMM. This integrative index, combining inflammation, IR, and central obesity, outperforms its components, offering a practical tool for early identification of high-risk individuals for targeted prevention.