Predictive value of neutrophil to lymphocyte ratio in patients with acute ST segment elevation myocardial infarction after percutaneous coronary intervention: a meta-analysis

BACKGROUND: The neutrophil to lymphocyte ratio (NLR) is an indicator of systemic inflammation and a prognostic marker in patients with acute coronary syndrome (ACS). This study aims to investigate the value of NLR to predict the in-hospital and long-term prognosis in patients with ST segment elevation myocardial infarction (STEMI) after percutaneous coronary intervention (PCI) by meta-analysis. METHOD: The studies related to the prognosis of NLR and STEMI patients published in the Pubmed, Embase, and Ovid databases before June 2017 were retrieved. The relevant data were extracted. Review Manager Version 5.3 was used for meta-analysis. RESULTS: A total of 14 studies of 10,245 patients with STEMI after PCI were included. A significant difference was observed for mortality (P < 0.001; relative risk (RR) 3.32; 95% confidence interval (CI) 2.45–4.49), hospital cardiac mortality(P < 0.001; RR 3.22; 95% CI 2.25–4.60), all mortality (P < 0.001; RR 3.23; 95% CI 2.28–4.57), major adverse cardiovascular events (MACE) (P < 0.001; RR 2.00; 95% CI 1.62–2.46), in-stent thrombosis (P < 0.001; RR 2.72 95% CI 1.66–4.44), nonfatal myocardial infarction(MI) (P < 0.001; RR 1.93; 95%CI 1.43–2.61), angina (P = 0.007; RR 1.67; 95%CI 1.15–2.41), advanced heart failure (AHF) (P < 0.001; RR 1.81; 95% CI 1.48–2.21), arrhythmia (P = 0.002; RR 1.38; 95% CI 1.13–1.69), no reflow (P < 0.001; RR 2.28; 95% CI 1.46–3.57), long-term all mortality (P < 0.001; RR 3.82; 95% CI 2.94–4.96), cardiac mortality (P = 0.004; RR 3.02; 95% CI 1.41–6.45), MACE (P < 0.001; RR 2.49; 95% CI 1.47–4.23), and nonfatal MI (P = 0.46; RR 1.32; 95% CI 0.63–2.75). CONCLUSIONS: Meta-analysis shows that NLR is a predictor of hospitalization and long-term prognosis in patients with STEMI after PCI, but requires further confirmation by large randomized clinical trials. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12872-018-0812-6) contains supplementary material, which is available to authorized users.