Neutrophil To Lymphocyte Ratio Predicts Symptomatic Intracranial Hemorrhage And Poor Outcome After Reperfusion Therapy In Acute Ischemic Stroke:A Meta-analysis

Objectives:The purpose of this study was to investigate whether baseline neutrophil to lymphocyte ratio（NLR）was an independent predictor for poor functional outcome or mortality at 3 months,and early symptomatic intracranial hemorrhage（sICH）after reperfusion therapy in patients suffering acute ischemic stroke with observational studies by meta-analysis.Methods:Using PubMed and EMBASE,we searched for literature published January19^th,2019 or earlier.Two reviewers independently confirmed each study’s eligibility,assessed risk of bias,and extracted data.One reviewer combined studies using random effects meta-analysis.We evaluated the following outcomes:symptomatic intracranial hemorrhage,poor functional outcome at 3 months（modified Rankin Score,mRS>2 or≥2）and 3-month death.Data extracted were converted into standardized mean differences（SMD）and effect sizes（ES）,and statistics were calculated by using StataSE12.Results:Of the 473 initially identified literatures,9 observational studies with 3651patients were finally pooled in meta-analysis.Overall,baseline NLR levels were greater in patients with sICH,poor functional outcome,and death at 3 month.The standardized mean difference in the NLR levels between the patients with poor functional outcome（mRS>2）and those without good outcome（mRS≤2）was 0.54 units（95%confidence interval 0.38 to0.70）.The test for overall effect z-score is 6.56（p<0.001）.Heterogeneity test showed that there were significant differences between individual studies（p=0.02;I2=72.8%）.Across a total of 4 studies included referring to sICH,the NLR level was related with sICH（SMD=0.78,95%credible interval[CI]=[0.18,1.38],I2=73.9%）.Higher NLR level was associated with 3-month death（ES=1.71,95%CI[1.01,2.42],p<0.01,I2=0%）.Conclusion:Our meta-analysis suggests that greater NLR levels are associated with increased risk of sICH,3-month poor functional outcome and 3-month death in acute ischemic stroke patients undergoing reperfusion treatments including intravenous thrombolysis or mechanical thrombectomy or both,although there was significant heterogeneity across the studies.The use of NLR levels in predicting poor outcomes after reperfusion therapy in patients suffering acute ischemic stroke appears promising but requires further study.