Estimated small dense low-density lipoprotein cholesterol and incident myocardial infarction in patients undergoing dialysis: a nationwide cohort study
Abstract
Abstract Background Small dense low-density lipoprotein cholesterol (sdLDL-C) is an atherogenic LDL subfraction that may reflect lipid-related coronary risk beyond conventional cholesterol levels. Estimated sdLDL-C (E-sdLDL-C) is calculated from a standard lipid panel, but its prognostic relevance for myocardial infarction in patients undergoing dialysis remains uncertain. Methods This nationwide cohort study included 21,671 adults with end-stage kidney disease (ESKD) receiving long-term dialysis who underwent health screening in 2009–2017. E-sdLDL-C was calculated from fasting lipid profiles and categorised into quartiles. Incident myocardial infarction and ischemic stroke were the primary and secondary outcomes, respectively, assessed through December 2022. Results During 166,428 person-years, 993 myocardial infarctions occurred, with 9,426 deaths before myocardial infarction. Fully adjusted hazard ratios for myocardial infarction in Quartiles 2–4 versus Quartile 1 were 1.24 (95% CI, 1.01–1.52), 1.61 (1.32–1.96), and 1.44 (1.15–1.80), respectively. The association remained significant after accounting for competing mortality. For ischemic stroke, 1,249 events and 9,254 competing deaths occurred during 165,727 person-years, with no significant association with E-sdLDL-C after full adjustment. Adding E-sdLDL-C increased the C-index for myocardial infarction from 0.716 to 0.726 (Δ = 0.010), without significant differences from models including LDL-C (0.725; p = 0.453) or non-HDL-C (0.727; p = 0.264). Conclusion Among patients undergoing long-term dialysis, E-sdLDL-C was associated with incident myocardial infarction after multivariable adjustment, whereas no significant association was observed with ischemic stroke. These findings support the potential relevance of E-sdLDL-C for myocardial infarction risk assessment in patients with ESKD, although its clinical utility requires further validation.