Small Dense Low-density Lipoprotein Cholesterol as a Prognostic Risk Factor in Premature Acute Coronary Syndrome with...

Small dense low-density lipoprotein cholesterol (sdLDL-C) is recognized as an atherogenic risk factor. This study investigated the prognostic significance of sdLDL-C levels in patients with premature acute coronary syndrome (PACS) and multivessel disease (MVD).

This retrospective study enrolled 847 hospitalized patients diagnosed with PACS and MVD between May 2022 and November 2023. Patients were stratified based on clinical outcomes and tertiles of sdLDL-C levels. Multivariate Cox proportional hazard models were applied to determine whether or not sdLDL-C was a prognostic risk factor for major adverse cardiovascular events (MACEs). Cumulative event curves were estimated using the Kaplan-Meier method. The predictive efficacy of sdLDL-C for MACEs was assessed through a time-dependent receiver operating characteristic (ROC) analysis. In addition, a restricted cubic spline (RCS) analysis was conducted to explore the relationship between sdLDL-C levels and the risk of MACEs.

During a median follow-up of 12 months (interquartile range: 9-15 months), 124 MACEs (14.64%) were observed. The sdLDL-C levels in the MACEs group were significantly higher compared to the non-MACEs group (P＜0.001). A multivariate Cox hazards regression analysis revealed that the risk of MACEs in the highest sdLDL-C tertile group was 2.38 times greater than in the lowest tertile group (hazard ratio [HR]: 2.38, 95% confidence interval [CI]: 1.42-4.00; P = 0.001). Furthermore, each 1-mg/dL increase in sdLDL-C levels corresponded to a 12.2% increase in the risk of MACEs (HR: 1.12, 95% CI: 1.08-1.16; P＜0.001). A Kaplan-Meier survival analysis identified significant differences in event-free survival among sdLDL-C tertiles (log-rank test, P＜0.001). The time-dependent ROC analysis demonstrated a progressive increase in the area under the curve during the follow-up period, particularly within the first 12 months. The RCS analysis revealed a nonlinear dose-response relationship between higher sdLDL-C levels and increased cumulative risk of MACEs (P_nonlinear = 0.001).

sdLDL-C is a predominant predictor of a poor prognosis in patients with PACS and MVD, underscoring its clinical relevance for risk stratification and the early identification of high-risk individuals who may benefit from targeted intervention.