Neutrophil to Lymphocyte Ratio and Spontaneous Bacterial Peritonitis among Cirrhotic Patients: A Systematic Review and Meta-analysis

BACKGROUND: The goal of this systematic review and meta-analysis was analyzing published studies on the role of neutrophil to lymphocyte ratio (NLR) in infection and spatially spontaneous bacterial peritonitis (SBP) among cirrhotic patients. METHODS: PubMed, Web of Science, and Scopus were searched until May 24, 2022. The Newcastle–Ottawa scale was used for quality assessment. RESULTS: Of 14 studies included in our study, six studies were on infection with 2786 hospitalized cirrhotic patients, of whom 934 developed an infection. Other studies were on SBP with 1573 cirrhotic patients with ascites, of whom 557 developed SBP. The pooled results showed that there was no difference in NLR levels between hospitalized cirrhotic patients who developed infection compared to those who did not (random-effects model: SMD = 0.63, 95% CI = −0.01–1.27, p=0.054). However, cirrhotic patients with ascites who developed SBP had elevated levels of NLR compared to those who did not (random-effects model: SMD = 1.05, 95% CI = 0.52–1.57,p < 0.001). This difference remained significant in prospective studies (SMD = 0.94, 95% CI = 0.51–1.38,p < 0.001) but not in retrospective studies (SMD = 1.37, 95% CI = −0.56–3.29,p=0.165), in the subgroup analysis according to the study design. The pooled sensitivity of NLR was 92.07% (95% CI = 74.85%–97.84%) and the pooled specificity was 72.58% (95% CI = 57.72%–83.69%). The pooled positive likelihood ratio, negative likelihood ratio, DOR of NLR were 3.35(95%CI = 2.06–5.46), 0.10 (95%CI = 0.03–0.38), and 30.78 (95%CI = 7.01–135.04), respectively. CONCLUSION: Our results support NLR to be a valid biomarker that can be readily integrated into clinical settings to help in the prevention and prediction of SBP among cirrhotic patients.