Neutrophil–lymphocyte count ratio as a diagnostic marker for acute kidney injury: a systematic review and meta-analysis

Background The neutrophil-to-lymphocyte ratio (NLR) is calculated from the white cell differential blood count. Recently, NLR was identified as a potential biomarker for the prediction of acute kidney injury (AKI). We conducted this systematic review and meta-analysis to evaluate the diagnostic value of NLCR for AKI in adult patients. Methods Studies in the PubMed, EMBASE, Web of Science and Cochrane Library databases were systematically searched from the date of database inception to February 28, 2019. The predictive value of NLR for AKI was evaluated by the pooled sensitivity, specificity, and summary receiver operating characteristic curve (SROC) analyses. Review Manager and Stata were used for all statistical analyses. The sources of potential heterogeneity were explored by a sensitivity analysis and subgroup analysis. Results This meta-analysis returned 89 reports, of which 9 fulfilled the inclusion criteria, accounting for 9766 patients. Bivariate analysis yielded a mean sensitivity of 0.736 (95% CI 0.675–0.790) and specificity of 0.686 (95% CI 0.601–0.759). The SROC was 0.77 (95% CI 0.74–0.81). The studies had no significant heterogeneity ( Q = 0.675, p = 0.357, I 2 = 0). Conclusions Our findings indicate that the NLR may be a reliable biomarker for the early detection of AKI. Our findings also provide important information and assistance for clinicians in the prediction of AKI.