INTRODUCTION: Patients with acute coronary syndrome (ACS) exhibit a wide spectrum of early risk of death (one to 10 percent). High platelet counts may indicate a propensity for platelet-rich thrombi. Lymphocyte counts drop during ACS due to stress-induced cortisol release. Combining these two markers, recent studies have found that the platelet-tolymphocyte ratio (PLR) is associated with adverse cardiac events among patients with ACS, but local data is limited. The objective of this study is to determine if an elevated PLR taken on admission is associated with higher rates of adverse cardiac events.

METHODS: A retrospective cohort of adult patients with ACS admitted at the UP-Philippine General Hospital was analyzed. Leukocyte and platelet counts were measured by an automated hematology analyzer. The PLR values of these patients were computed, and they were stratified into two groups after determining the optimal cut-off from the receiver operating characteristic curve (ROC) curve. The primary outcome was in-hospital mortality. Secondary outcomes included development of heart failure, cardiogenic shock, reinfarction, and significant arrhythmias.

RESULTS: A total of 174 Filipinos with ACS were included. In-hospital mortality occurred in 30 patients (17%). These patients had a higher PLR compared to those who were discharged alive (p-value <0.0001). The optimal cutoff value of PLR to predict in-hospital mortality is 165, with a sensitivity of 77% and specificity of 70% (area under the ROC curve of 0.766). On multiple logistic regression analysis, a high PLR was an independent predictor of in-hospital mortality (RR 8.52; p 0.003) after controlling for the effect of other variables. The development of the predetermined secondary outcomes did not correlate with PLR on multivariate analysis.

CONCLUSION: Among Filipino patients with ACS, an elevated PLR taken within 24 hours of admission is a useful marker to predict in-hospital mortality, thus providing vital information for risk stratification and more aggressive management strategies.