Exploring the relationship between remnant cholesterol and diabetic kidney disease in Chinese type 2 diabetes patients

Background Remnant cholesterol (RC) has been established as an independent risk factor for atherosclerotic cardiovascular disease. While the association between RC and diabetic kidney disease (DKD) remains unclear. Methods This cross-sectional study included 1,893 patients with T2D hospitalized across multiple centers from 2019 to 2024. The correlation of RC and DKD was analyzed by multiple logistic regression and restricted cubic spline (RCS) models. The subgroup analysis was to assess the stability of the correlation between RC and DKD. Results The participants comprise 1,340 without DKD and 553 with DKD. RC was significantly higher in DKD patients compared non-DKD patients ( P = 0.012). In multiple logistic regression analysis, the results revealed a 43% increased DKD risk per 0.1 mmol/L RC increment (adjusted OR = 1.43, 95% CI = 1.10–1.86). Additionally, when analyzed as quartiles, participants in the highest RC quartile (Q4: >0.700 mmol/L) demonstrated 1.77-fold higher DKD risk compared to the lowest quartile (95% CI = 1.28–2.45, P = 0.001), with significant linear trend across quartiles ( P < 0.001). Furthermore, RCS model demonstrated a biphasic relationship: risk increased linearly with RC levels below 0.96 mmol/L (β = 2.25 per 0.1 mmol/L, P = 0.001), transitioning to a plateau (β = 0.86, P = 0.588) with RC levels exceeded 0.96, suggesting lipid-mediated renal injury pathways may reach saturation. Subgroup analyses confirmed stability across demographic or clinical strata (all P > 0.05). Conclusions Our study establishes RC as an independent DKD biomarker in Chinese T2D patient, suggesting its dual utility as a pathophysiological indicator and preventive therapeutic target.