Association of remnant cholesterol with long-term outcomes in kidney transplant recipients: a retrospective cohort study

Post-transplant dyslipidemia is frequently observed and has been associated with graft survival. Traditional lipid parameters show inconsistent associations with graft outcomes, whereas remnant cholesterol (RC) may provide additional prognostic value; however, its role remains unclear in kidney transplant recipients. In this retrospective cohort of 1,943 living donor kidney transplant recipients, a 365-day landmark design was applied. Lipid exposure was defined as mean levels within the first year after transplantation, including RC, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), non-HDL-C, total cholesterol (TC), and triglycerides (TG). Multivariable Cox proportional hazards models were used to estimate adjusted hazard ratios, and restricted cubic spline analyses were used to explore potential dose–response patterns. Lipid parameters were additionally analyzed as categorical variables. Subgroup analyses assessed potential effect modification, and incremental value analyses evaluated model improvement. Elevated RC (HR 2.38, 95% CI: 1.26–4.50, P = 0.008) and TG (HR 1.38, 95% CI: 1.06–1.79, P = 0.015) were independently associated with higher allograft loss risk and showed dose–response patterns. Similar results were observed in categorical analyses. Non-HDL-C was not significantly associated with allograft loss in the primary analysis (HR 1.64, 95% CI: 1.00 – 2.70, P = 0.051), and LDL-C, HDL-C, and TC showed no consistent associations with graft outcomes. No lipid parameter was significantly associated with all-cause mortality. The TG–allograft loss association was stronger among recipients with fewer human leukocyte antigen mismatches ( P for interactio n = 0.012). Adding RC to the baseline risk model modestly improved model performance (ΔC-index = 0.008, P = 0.007; ΔAIC = − 4.78). Higher RC and TG levels were independently associated with an increased risk of kidney allograft loss in living donor recipients. RC showed the most consistent association with graft outcomes and modest improvement in model performance, supporting further evaluation of RC as an adjunctive marker in post-transplant lipid assessment and long-term graft care.