Neutrophil-to-lymphocyte Ratio Predicts Adverse Prognosis In Acute Ischemic Stroke Patients Treated With Intravenous Thrombolysis : A Meta-analysis

Objective:Intravenous thrombolysis(IVT)is a preferred treatment for acute ischemic stroke(AIS)patients within the time window.However,there are approximately 50% of the patients treated with IVT suffered neurological dysfunction and approximately 27%of the patients suffered hemorrhagic transformation(HT).Exploring the predictors for adverse outcomes may be helpful for clinicians to identify the high-risk groups of HT and poor functional outcome after IVT,thereby providing appropriate intervention measures to improve the prognosis.The neutrophil-to-lymphocyte ratio(NLR)is a readily available,repea table new inflammatory biomarker.Previous studies have shown that the NLR was associated with adverse prognosis after stroke.However,the relationship between the NLR and adverse prognostics in AIS patients who receive IVT remains controversial.The purpose of this meta-analysis is to comprehensively evaluate the relationship between the NLR and adverse prognosis in AIS patients treated with IVT.Methods:The Cochrane library,Pubmed,Embase,Wed of Science and China National Knowledge Infrastructure,Wanfang Database,VIP Database and Sino Med were searched for relevant articles until January 7,2021.Studies were included if they were related to the NLR in AIS patients treated with IVT.The Newcastle-Ottawa Scale(NOS)was used to evaluate the quality of the included studies.Odds ratios(ORs)and95% confidence intervals(CIs)were pooled to estimate the relationship between NLR and adverse prognosis after IVT.Results:Twelve studies,including 3641 patients,met the predefined inclusion criteria.The NOS scored 6-8 points,indicating that the included studies with high quality.Higher NLRs were associated with an increased risk of HT(OR=1.33,95%CI=1.14-1.56,P<0.001)and a poor 3-month functional outcome(OR=1.64,95%CI=1.38-1.94,P<0.001)in AIS patients receiving IVT.There was no statistically significant difference between higher NLRs and 3-month mortality(OR=1.14,95%CI=0.97-1.35,P=0.120).Subgroup analysis of HT suggested that the NLR at admission rather than the NLR after IVT was associated with an increased risk of HT(OR=1.33,95% CI=1.01-1.75,P=0.039).A higher risk of HT was observed in the elderly group(OR=1.32,95%CI=1.11-1.57,P=0.002)and in the studies excluding infection(OR=1.64,95%CI=1.14-2.35,P=0.008).An onset-to-IVT time less than 3 hours was associated with a higher risk of HT(OR=1.32,95% CI=1.11-1.57,P<0.001).Subgroup analysis of poor3-month functional outcomes suggested that the blood sample collection time,age,country,onset-to-IVT time and presence or absence of infection had no significant influence on the overall results.Higher NLRs were associated with a higher risk of poor functional outcome in the studies with moderate stroke severity(NIHSS≥8)(OR=2.15,95% CI=1.50-3.09,P<0.001).Conclusions:1.High NLR was an independent predictor of HT in AIS patients treated with IVT.NLR at admission rather than the NLR after IVT was associated with a higher risk of HT.2.High NLR was an independent predictor of poor 3-month functional outcome in AIS patients treated with IVT.3.There was no significant correlation between high NLRs and 3-month mortality in AIS patients treated with IVT.