Usefulness of Platelet-to-Lymphocyte Ratio to Predict Long-Term All-Cause Mortality in Patients at High Risk of Coronary Artery Disease Who Underwent Coronary Angiography

Abstract

Platelet-to-lymphocyte ratio (PLR) has recently been studied as a biomarker in patients with established coronary artery disease (CAD). The association between PLR and long-term all-cause mortality is unclear in patients at high risk of CAD who undergo coronary angiography for various indications. Follow-up was completed for 514 patients who underwent coronary angiography in a prospective study cohort. The primary end point was all-cause mortality. Patients were classified into tertiles based on preangiography PLR and also dichotomized based on the optimal cutoff at a PLR of 137, determined from the receiver operating characteristic curve analysis. The mean follow-up period was 5.0 ± 1.3 years, with 50 all-cause deaths. On the Kaplan-Meier analysis, patients in Tertile 3 (PLR > 145) had worse prognosis than patients in Tertiles 1 (PLR ≤ 106) and 2 (PLR 106.1 to 145) (p = 0.0075), and patients with PLR ≥ 137 had a significantly higher rate of all-cause mortality than those with PLR < 137 (p = 0.0006). On multivariate Cox regression adjusting for known cardiovascular risk factors, PLR was a strong, independent predictor of long-term all-cause mortality on the tertile analysis (Tertile 3 vs Tertile 1: hazard ratio 2.52, 95% confidence interval 1.18 to 5.39, p = 0.017) and based on the cutoff at a PLR of 137 (PLR ≥ 137 vs <137: hazard ratio 2.25, 95% confidence interval 1.21 to 4.20, p = 0.011). In conclusion, elevated PLR is associated with long-term all-cause mortality in patients at high risk of CAD who undergo coronary angiography, and PLR may be a useful prognostic biomarker in this population.