Associations between lipid-derived indices and cardiovascular–kidney–metabolic syndrome progression among Chinese middle-aged and elderly adults: a longitudinal study

Background The cardiovascular–kidney–metabolic syndrome (CKM) underscores the pathological interconnections between metabolic abnormalities, chronic kidney disease (CKD), and cardiovascular disease (CVD). Lipid metabolism is closely associated with the pathophysiology of these diseases. This study aimed to investigate the associations between eight lipid-derived indices and the progression of CKM syndrome. Methods This study utilized data from the 2011–2020 China Health and Retirement Longitudinal Study (CHARLS). Lipid-derived indices were included: the atherogenic index of plasma (AIP), non-high-density lipoprotein cholesterol (Non-HDL-C), the non-HDL-C to HDL-C ratio (NHHR), the lipoprotein combined index (LCI), the remnant cholesterol (RC), the lipid accumulation product (LAP), the visceral adiposity index (VAI), and the triglyceride-glucose ratio (TyG). Cox regression analysis and restricted cubic spline (RCS) modeling were employed to assess the associations between lipid-derived indices and progression to CVD in the CKM syndrome stage 0–3 population. A comparison of prediction performance was conducted via the concordance index (C-index). Logistic regression and RCS models were used to analyze the associations between lipid-derived indices and the progression of CKM syndrome. Results After adjusting for potential confounders, all lipid-derived indices, except for RC, exhibited positive associations with the risk of CVD in the CKM syndrome stages 0–3 population. The Cox regression model revealed that the AIP, non-HDL-C, NHHR, LCI, LAP, VAI, and TyG were positively associated with the risk of CVD. The RCS models demonstrated that the AIP, NHHR, LCI, and TyG were linearly associated with CVD risk, whereas the LAP and VAI exhibited nonlinear associations with CVD risk. The predictive model incorporating NHHR demonstrated the highest performance, with a C-index of 0.6322. Similarly, all lipid-derived indices, except RC, were positively correlated with the progression of CKM syndrome, as determined by logistic regression analysis. Conclusion Seven lipid-derived indices—AIP, non-HDL-C, NHHR, LCI, LAP, VAI, and TyG—were positively associated with the risk of CVD in individuals diagnosed with CKM syndrome across stages 0–3. The NHHR demonstrated a stronger predictive value for CVD risk. Additionally, the seven indices were positively correlated with the progression of CKM syndrome, suggesting that these lipid-derived indices are important predictors of CKM progression.