Neutrophil-lymphocyte ratio and platelet-lymphocyte ratio use in detecting bowel ischaemia in adhesional small bowel obstruction

Background: Bowel ischaemia significantly increases morbidity and mortality from adhesional small bowel obstruction. Current biomarkers and clinical parameters have poor predictive value for ischaemia. Our study investigated whether neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) could be used to predict bowel ischaemia in adhesional small bowel obstruction. Methods: This single-centre retrospective study collected clinical, biochemical and radiological data from patients with adhesional small bowel obstruction between 2017 and 2020 who underwent operative management. The presence or absence of bowel ischaemia/infarction was used to distinguish two populations. Biochemical markers on admission and immediately prior to operation were collected to give platelet-lymphocyte ratio (PLR₀ and PLR_PRE-OP, respectively) and neutrophil-lymphocyte ratio (NLR₀ and NLR_PRE-OP, respectively). SAS 9.4 (SAS Institute Inc., Cary, NC) software was used for data analysis with Mann-Whitney U testing for continuous variables and Pearson Chi-square test for categorical variables. Sensitivity and specificity for PLR and NLR were calculated by means of receiver operating characteristic (ROC) curve analysis. Results: Twenty-seven patients had intra-operative bowel ischaemia whilst the remaining 73 had no evidence of bowel ischaemia. Both median PLR_PRE-OP and NLR_PRE-OP were significantly higher in patients with bowel ischaemia compared to those without (PLR_PRE-OP 272 [IQR 224-433] and 231 [IQR 146-295] respectively, P = 0.027; NLR_PRE-OP 12.5 [IQR 8.6-21.3] v. 5.5 [IQR 3.5-10.2] respectively, P ≤0.001). Area under the receiver operator characteristic curve (AUC) was 0.762 for NLR_PRE-OP, with a sensitivity of 85.1% and specificity of 63% for NLR 7.4. Conclusion: Raised NLR is predictive of bowel ischaemia in patients with adhesional small bowel obstruction.