Association of the Platelets to High Density Lipoprotein Cholesterol Ratio and Risk of Heart Disease Events in Middle-Aged and Elderly Chinese Population: A Retrospective Cohort Study Utilizing the CHARLS Database.

Background: The association between the platelet to high-density lipoprotein cholesterol ratio (PHR) and the risk of a heart disease event remains unclear. This study aims to determine whether the PHR can identify individuals at high risk for heart disease events, with a particular focus on middle-aged and elderly Chinese individuals.

Methods: The retrospective cohort study encompassed 7188 middle-aged and elderly participants (>45 years) sourced from the China Health and Retirement Longitudinal Study (CHARLS) database. This research utilized longitudinal data from 5 follow-up visits spanning 2011 to 2020, which encompassed the collection of demographic profiles and pertinent blood biomarkers. Kaplan-Meier survival analysis was conducted based on PHR quartiles, with differences assessed using the log-rank test. The Cox proportional hazards model evaluated PHR's hazard ratio (HR) as a predictor of outcome events, with trend tests applied. Restrictive cubic splines (RCS) were employed to explore associations. Subgroup analyses were performed to validate the robustness of the findings.

Results: Baseline comparisons across quartiles of the PHR revealed a progressive increase in PHR values (133.16 vs 202.09 vs 267.04 vs 388.24), which corresponded to ascending incidence rates of heart disease (18.20% vs 18.64% vs 18.86% vs 21.59%) (p < 0.05). The Kaplan-Meier survival analysis of PHR quartile groups revealed a notable elevation in the incidence of cardiovascular events in Q4 compared to Q1, Q2, and Q3 throughout the follow-up period (log-rank p < 0.05). Upon adjustment for age, gender, stroke history, drinking, smoking, body mass index (BMI), white blood cell (WBC) count, fasting plasma glucose (FPG), creatinine (Cr), and triglyceride (TG), the Q4 group continued to exhibit a significantly elevated HR relative to Q1 (HR = 1.203, p = 0.023). Furthermore, RCS affirmed a linear association between PHR and heart disease events (Adjusted: Overall p = 0.014, Nonlinear p = 0.588). When analyzing by gender, high PHR was a risk factor for males (Q4: HR = 1.352, p = 0.019), but not for females (Q4: HR = 1.158, p = 0.166). Subgroup analysis indicates a significant association between higher PHR levels and increased risk of cardiac events compared to lower levels.

Conclusions: Our study reveals a positive correlation between PHR levels and the incidence of heart disease events in middle-aged and elderly men in China. However, no such correlation was observed in female patients.