title: Neutrophil to lymphocyte ratio in relation to risk of all-cause mortality and cardiovascular events among patients undergoing angiography or cardiac revascularization: a meta-analysis of observational studies.
abstract: OBJECTIVE
  The aim of this study was to investigate whether neutrophil to lymphocyte ratio (NLR) was an independent predictor for all-cause mortality or cardiovascular events in patients undergoing angiography or cardiac revascularization with observational studies by meta-analysis.
  
  
  METHODS
  Pubmed and Embase were searched without language restrictions for cohort studies published prior to November 2013. Citations were independently screened by 2 authors, and those meeting the inclusion criteria defined a priori were retained. Data on authors, year of publication, location, target participant, comparison of NLR, outcome assessment, number of event and sample size, duration and statistical adjustments were abstracted.
  
  
  RESULTS
  Eight studies were identified that reported on all-cause mortality and five studies were identified that reported on cardiovascular events. The pooled relative risk (RR) of all-cause mortality was 2.33 (95% CI 1.88-2.88) and the RR of cardiovascular events was 1.89 (95% CI 1.42, 2.52) comparing the highest with the lowest category of NLR.
  
  
  CONCLUSIONS
  The meta-analysis indicates that NLR is a predictor of all-cause mortality and cardiovascular events. Further well-designed trials are warranted to confirm this association.
authors.affiliation: Department of Cardiology, Renmin Hospital of Wuhan University, China.
authors.forename: Xiaoding
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Cardiology, Zhongnan Hospital of Wuhan University, China.
authors.forename: Guangyu
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, Renmin Hospital of Wuhan University, China. Electronic address: xjjiang@whu.edu.cn.
authors.forename: Xuejun
authors.initials: X
authors.lastname: Jiang
authors.affiliation: Department of Cardiology, Renmin Hospital of Wuhan University, China.
authors.forename: Hongling
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Department of Cardiology, Renmin Hospital of Wuhan University, China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Lu
authors.affiliation: Department of Cardiology, Renmin Hospital of Wuhan University, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Xu
mesh_terms: D002318:Cardiovascular Diseases / Q000097:blood* / Q000453:epidemiology*; D002423:Cause of Death; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000097:blood* / Q000000981:diagnostic imaging / Q000401:mortality* / Q000601:surgery; D006801:Humans; D007958:Leukocyte Count; D008214:Lymphocytes; D009204:Myocardial Revascularization; D009504:Neutrophils; D064887:Observational Studies as Topic; D018570:Risk Assessment
keywords: All-cause mortality; Cardiovascular events; Meta-analysis; Neutrophil/lymphocyte ratio