The U-shape relationship between platelet/high-density lipoprotein cholesterol ratio and 1-year all-cause mortality in acute coronary syndrome patients: a retrospective cohort study

The platelet/high-density lipoprotein cholesterol ratio (PHR) reflects the balance between platelet activity and lipid metabolism. This study aimed to investigate the association between PHR and 1-year all-cause mortality in patients with acute coronary syndrome (ACS) and to characterize the nature of this association. Patients with ACS who were hospitalized at the Affiliated Hospital of Guangdong Medical University between January 2022 and December 2023 were retrospectively enrolled. The patients were divided into four equal quartiles based on their PHR levels. The primary outcome was 1-year all-cause mortality, and the secondary endpoint was major adverse cardiovascular and cerebrovascular events (MACCE). Multivariate Cox proportional hazards regression, two-piecewise linear regression, and restricted cubic spline (RCS) methods were used to analyze the associations of PHR with all-cause mortality and MACCE. Of the 1317 enrolled participants (median age 67 years), 134 (10.17%) died and 273 (20.73%) experienced MACCE within the 1-year follow-up. After full adjustment, participants in the lowest PHR quartile (Q1) (adjusted hazard ratio [HR]: 2.077, 95% confidence interval [CI] 1.230–3.507, P = 0.006) and the highest PHR quartile (Q4) (adjusted HR: 2.420, 95% CI 1.411–4.151, P = 0.001) exhibited significantly higher risks of 1-year all-cause mortality compared with those in the third quartile (Q3). RCS analysis revealed a nonlinear association between PHR and 1-year all-cause mortality. The two-piecewise linear regression model identified an inflection point at 213.60 (95% CI 130.61–244.96). A similar U-shaped association was observed for MACCE. The PHR shows a U-shaped association with 1-year all-cause mortality among ACS patients, with both low and high levels associated with an increased risk of mortality. A similar U-shaped association was also identified between PHR and MACCE. Trial registration The details of the design were registered on https://www.chictr.org.cn/ (registration number: ChiCTR2500110802; registration date: 21 October 2025).