Neutrophil Lymphocyte Ratio in Outcome Prediction After Emergency Abdominal Surgery in the Elderly

Introduction: Accurate prediction of outcome after emergency surgery in elderly patients may assist decision-making. Many scoring systems require post-operative data (e.g. P-POSSUM) whilst others have failed to gain widespread use. Recent reports suggest that C-reactive protein (CRP) and the neutrophil lymphocyte (N/L ratio) ratio may predict surgical outcome.

Methods: A retrospective review of all patients aged 80 years or over undergoing emergency abdominal surgery over a 22 month period was conducted. Outcome and clinical data were collected. Univariate, multivariate and recursive analyses were performed for outcome at 30 days, 6 months and 12 months. Findings were validated in a second independent dataset.

Results: 88 patients were included in the test dataset, median age 84 years. 30-day mortality was 31%, 6-month mortality 43% and 12-month mortality 50%. Univariate analysis identified N/L ratio, CRP, midline laparotomy, and surgical risk score to predict outcome at each time point. Recursive analysis showed, N/L ratio ≥22 best predicted 30-day outcome (p=0.0018). Multivariate analysis identified N/L ratio to be an independent predictor of 30-day outcome (p=0.004) yet CRP did not predict outcome at any time point. An independent dataset (n=84) confirmed N/L ratio to be a prognostic factor at 30 days (p=0.001), 6 months (p<0.001) and 12 months (p=0.001).

Conclusion: N/L ratio is an easily calculable pre-operative measure that may have utility in the prediction of outcome after emergency abdominal surgery in the elderly. Further work to validate this measure in a larger, prospective setting and determine the underlying mechanisms that mediate outcome are necessary.