Platelet-to-Lymphocyte Ratio Improves the Predictive Power of GRACE Risk Score for Long-Term Cardiovascular Events in Patients with Acute Coronary Syndrome

<b><i>Objectives:</i></b> This study aims to evaluate the relationship between platelet-to-lymphocyte ratio (PLR) and GRACE risk score and to examine whether PLR on admission can improve the predictive value of GRACE risk score for cardiovascular disease (CVD) events in patients with acute coronary syndrome (ACS). <b><i>Methods:</i></b> PLR was calculated from the platelet and lymphocyte counts from the complete blood count of 2,230 ACS patients upon admission. The GRACE risk score was also calculated. <b><i>Results:</i></b> Spearman's rank correlation demonstrated that GRACE risk score was positively correlated with PLR (r = 0.190, p < 0.001). After a median follow-up period of 58 months, multivariate Cox analysis showed that both GRACE risk score [hazard ratio (HR) 1.092, 95% confidence interval (CI) 1.067-1.117, p < 0.001] and PLR (HR 1.100, 95% CI 1.088-1.112, p < 0.001) could independently predict CVD events. Receiver-operating characteristic curve (ROC) analysis proved that using PLR together with GRACE risk score improved the score from 0.70 (95% CI 0.67-0.73, p < 0.001) when used alone to 0.81 (95% CI 0.79-0.83, p < 0.001) for CVD events and from 0.73 (95% CI 0.70-0.77, p < 0.001) when used alone to 0.80 (95% CI 0.77-0.83, p < 0.001) for all-cause mortality. <b><i>Conclusions:</i></b> This study proves, for the first time, a positive association between GRACE risk score and PLR, and that a combination of PLR and GRACE risk score is more effective in predicting CVD events in ACS patients.