The prognostic value of platelet-to-lymphocyte ratio in patients with acute coronary syndrome: a systematic review and meta-analysis

Introduction: Acute coronary syndrome (ACS) is an important cause of death. It is important to identify factors predicting mortality of these patients. The aim of this systematic review was to evaluate the prognostic role of platelet-to-lymphocyte ratio (PLR) in patients with ACS. Materials and Methods: PubMed, Embase and Web of Knowledge databases were searched for relevant studies in, December 29th 2018. Studies investigating the association of PLR with mortality of ACS patients were included in the systematic review. Data extraction and quality assessment are performed independently by two authors. Meta-analysis of hazard ratios and the results of diagnostic statistical methods was performed. Results: A total of Thirteen studies with 17111 participants were included in the systematic review. Significant association between PLR and mortality rate was observed in all but one study. The pooled hazard ratios of short-term and long-term mortality in high PLR group compared to low PLR group were 2.187 (CI95: 1.56-3.06) and 2.40 (CI95: 1.69-3.42), respectively. Moreover, PLR showed a moderate prognostic accuracy for short-term and long-term mortality with area under the SROC curves of 0.710 and 0.668, respectively. Conclusion: PLR is significantly associated with mortality in ACS patients and can be used alone or in combination with other prognostic markers and scoring systems to stratify the risk of these patients.