Platelet-to-high-density lipoprotein cholesterol ratio and risk of major adverse cardiovascular events in patients with type 2 diabetes: A real-world retrospective cohort study.

BACKGROUND: Despite advances in evidence-based treatment, patients with type 2 diabetes mellitus (T2DM) remain at substantial cardiovascular risk. The platelet-to-high-density lipoprotein cholesterol ratio (PHR) integrates platelet-related thrombotic activity and HDL-related vascular protection, but its association with major adverse cardiovascular events (MACE) in real-world T2DM populations remains uncertain. We investigated the association of baseline PHR with MACE and its incremental prognostic value. METHODS: This single-center retrospective cohort included 11,624 patients with T2DM. PHR was calculated as platelet count (×109/L) divided by high-density lipoprotein cholesterol (mmol/L). Kaplan-Meier curves, multivariable Cox proportional hazards models, and restricted cubic splines were used to evaluate the association between baseline PHR and MACE (cardiovascular death, non-fatal myocardial infarction, or non-fatal stroke). Subgroup and sensitivity analyses assessed robustness, longitudinal reproducibility was evaluated among participants with repeated measurements, and incremental prognostic value was assessed using discrimination, reclassification, and calibration measures. RESULTS: During a median follow-up of 28.8 months (IQR, 5.0-67.5 months), 2190 patients (18.84%) experienced MACE. Each 1-SD higher baseline PHR was independently associated with a 20% higher MACE risk (HR, 1.20; 95% CI, 1.15-1.25; P < 0.001). Restricted cubic spline analysis indicated an approximately linear association, and no significant interactions were observed across the examined subgroups. Among participants with repeated measurements, PHR showed moderate longitudinal reproducibility (ICC, 0.68; 95% CI, 0.66-0.70). Adding PHR increased the C-index from 0.625 to 0.632 (ΔC-index, 0.007), indicating a modest improvement in predictive performance. CONCLUSIONS: Higher baseline PHR was independently associated with an increased risk of MACE in patients with T2DM. As an inexpensive and routinely available biomarker, PHR may provide modest supplementary information for comprehensive cardiovascular risk assessment.