Predictive value of remnant cholesterol inflammatory index for cardiovascular-kidney-metabolic syndrome progression: A prospective cohort study

Cardiovascular-kidney-metabolic (CKM) syndrome is a progressive disorder resulting from the intricate interactions among obesity, diabetes, chronic kidney disease (CKD), and cardiovascular disease (CVD). Remnant cholesterol (RC) has been shown to be associated with the risk of CKM syndrome progression. However, the combined effects of RC and high-sensitivity C-reactive protein (hs-CRP) on CKM syndrome progression remain unclear. This study evaluated the association between the remnant cholesterol inflammatory index (RCII) and CKM progression risk. Data from the China Health and Retirement Longitudinal Study (CHARLS) were analyzed. Logistic regression models were employed to investigate the association between the baseline RCII and advanced CKM stages. Kaplan-Meier analysis was conducted to assess the cumulative incidence of CVD across RCII quartiles in individuals with CKM stages 0–3. Cox regression models were used to examine the associations of the baseline and cumulative RCII (CumRCII) with the risk of new-onset CVD among individuals with CKM stages 0–3. In the baseline analysis, each standard deviation (SD) increase in the RCII was associated with a 26% greater risk of advanced CKM stages (odds ratio (OR): 1.26, 95% CI: 1.20–1.34). During the 7-year follow-up, 1483 (21.5%) participants with CKM stages 0–3 developed CVD. The cumulative incidence of CVD progressively increased across RCII quartiles, from 17.02% in Q1 to 25.75% in Q4. After full adjustment, compared with that in RCII Q1, CVD risk was 19% greater in Q3 (hazard ratio (HR): 1.19, 95% CI: 1.02–1.39) and 29% greater in RCII Q4 (HR: 1.29, 95% CI: 1.11–1.51). Participants with CumRCII levels that exceeded 29.49 had a significantly increased risk of new-onset CVD (HR: 1.41, 95% CI: 1.10–1.80). Higher baseline RCII and CumRCII were associated with an increased CVD risk in participants with CKM stages 0 – 3. Early intervention in those with elevated RCII may help prevent CKM progression. • Nationwide Cohort Evidence: This study was based on a large, nationally representative prospective cohort of Chinese adults aged ≥45 years. • Significant Association Identified: Baseline RCII was an independent risk factor for advanced CKM syndrome stages. Both higher baseline RCII and CumRCII were associated with a greater risk of incident CVD among participants with CKM stages 0-3. • Potential as a Clinical Predictor: RCII may serve as a potential biomarker for early identification and intervention in individuals at high risk for CKM progression.