Platelet-to-Lymphocyte Ratio at Admission as a Predictor of In-Hospital and Long-Term Outcomes in Patients With ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention: A Systematic Review and Meta-Analysis

BACKGROUND: ST-segment elevation myocardial infarction (STEMI) is the most severe form of acute coronary syndrome (ACS) which is associated with significant adverse outcomes. Platelet-to-lymphocyte ratio (PLR) is a novel inflammatory biomarker that has been used as a predictor of various cardiovascular diseases, including ACS. This meta-analysis aimed to investigate the prognostic value of PLR as a predictor of in-hospital and long-term outcomes in patients with STEMI undergoing primary percutaneous coronary intervention (PCI). METHODS: We performed a comprehensive systematic literature search in the databases of PubMed, ScienceDirect, Cochrane Library, and ProQuest for eligible studies. The primary outcomes were major adverse cardiac events (MACEs) and mortality, both in-hospital and long-term follow-up. The outcomes were compared between patients with high and low admission PLR. The quality assessment was conducted using the Newcastle-Ottawa scale. Review Manager 5.3 was used to perform the meta-analysis. RESULTS: Six cohort studies involving 4,289 STEMI patients undergoing primary PCI were included in this meta-analysis. The pooled analysis showed that a high PLR at admission was associated with increased in-hospital MACE (odds ratio (OR) = 1.94, 95% confidence interval (CI) = 1.56 - 2.40, P < 0.00001, I(2) = 45%) and in-hospital mortality (OR = 2.07; 95% CI = 1.53 - 2.80; P < 0.00001; I(2) = 50%), as well as increased long-term MACE (OR = 1.98; 95% CI = 1.31 - 3.00; P = 0.001; I(2) = 72%) and long-term mortality (OR = 2.79; 95% CI = 1.45 - 5.36; P = 0.002; I(2) = 83%). CONCLUSIONS: In patients with STEMI undergoing primary PCI, a high PLR at admission predicts in-hospital MACE and mortality along with long-term MACE and mortality.