Neutrophil‐to‐lymphocyte ratio predicts hemorrhagic transformation in ischemic stroke: A meta‐analysis

INTRODUCTION: The neutrophil‐to‐lymphocyte ratio (NLR) has been shown to be a marker associated with inflammation and is independently associated with the adverse clinical outcomes of symptomatic intracranial hemorrhage, cancer, and cardiovascular disease. Hemorrhagic transformation (HT) is a serious complication of ischemic cerebral infarction and can be intensified by therapeutic interventions for acute ischemic stroke (AIS). The purpose of our research was to explore the predictive effect of NLR for HT in patients with AIS and to determine the best predictive value. METHODS: PubMed, Web of Science, EMBASE, MEDLINE, Cochrane, and Google Scholar were searched. The primary endpoint was HT, and subgroup analysis was performed. Review Manager software version 5.3 was used to statistically analyze the outcomes. RESULTS: A total of seven studies including 3,726 patients met the inclusion criteria. The pooled odds ratio (OR) value of the high NLR that predicted HT in AIS patients was 1.53 (95% CI, 1.21–1.92; p = .0003). In addition, 1.10 (95% CI, 1.05–1.15; p < .0001) was the pooled OR of the high NLR associated with increased 3‐month mortality in patients with AIS. In the subgroup analysis with an NLR cutoff value of 7.5–11, the correlation between NLR above the cutoff value and the rate of HT in patients with AIS was statistically significant (OR, 7.93; 95% CI, 2.25–27.95; p = .001). CONCLUSION: A high NLR can predict HT and 3‐month mortality in patients with AIS. Regardless of the country of origin and the sampling time, an NLR with a cutoff value of 7.5–11 was independently associated with HT in AIS patients.