Association between C-reactive protein-triglyceride-glucose index and risk of stroke in different renal function status: a national cohort study

BACKGROUND: The C-reactive protein-triglyceride-glucose index (CTI), a novel biomarker integrating inflammation and insulin resistance, has been linked to cardiovascular disease. However, its association with stroke risk across varying levels of renal function remains unclear. METHODS: This prospective cohort study included 8,808 participants aged ≥ 45 years from the China Health and Retirement Longitudinal Study (CHARLS), covering the period 2011 to 2018. CTI was calculated as 0.412×Ln (CRP [mg/L]) + Ln (TG [mg/dL]×FPG [mg/dL])/2. Multivariable Cox models and restricted cubic splines were employed to assess the association between CTI and incident stroke. We stratified the analysis by estimated glomerular filtration rate (eGFR) and introduced interaction terms between CTI and eGFR levels to evaluate potential effect modification. RESULTS: = 0.289). Notably, we observed significant interaction between CTI and eGFR levels on stroke risk (P = 0.037). The association was markedly stronger in individuals with mildly reduced renal function (eGFR 60-89 mL/min/1.73 m²), where the highest CTI quartile (Q4) had an HR of 2.73 (95% CI: 1.16-6.40) compared to the Q1. Conversely, no significant associations were observed in participants with preserved (eGFR ≥ 90 mL/min/1.73 m²) or moderately-to-severely reduced renal function (eGFR < 60 mL/min/1.73 m²). CONCLUSION: Elevated CTI levels are associated with an increased risk of stroke in middle-aged and older Chinese adults, particularly among individuals with mild renal impairment. By combining inflammatory and metabolic markers, CTI might offer potential clinical value for risk assessment.