Clinical Significance of the Neutrophil–Lymphocyte Ratio as an Early Predictive Marker for Adverse Outcomes in Patients with Acute Cholangitis

Background and objectives: Acute cholangitis can be life-threatening if not recognized early. We investigated the predictive value of the neutrophil–lymphocyte ratio (NLR) in acute cholangitis. Materials and Methods: We retrospectively evaluated 206 patients with acute cholangitis who underwent biliary drainage. The severity of acute cholangitis was graded according to the Tokyo 2018 guideline. Patients were dichotomized according to the acute cholangitis severity (mild/moderate vs. severe), the presence of shock requiring a vasopressor/inotrope, and blood culture positivity. The baseline NLR, white blood cell (WBC) count, and C-reactive protein (CRP) levels were compared between groups. Results: The severity of acute cholangitis was graded as mild, moderate, or severe in 71 (34.5%), 107 (51.9%), and 28 (13.6%) patients, respectively. Ten patients (4.8%) developed shock. Positive blood culture (n = 50) was observed more frequently in severe acute cholangitis (67.9% vs. 17.4%, p < 0.001). The NLR was significantly higher in patients with severe cholangitis, shock, and positive blood culture. The area under the curve (AUC) for the NLR, WBC, and CRP for severe acute cholangitis was 0.87, 0.73, and 0.74, respectively. The AUC for the NLR, WBC, and CRP for shock was 0.81, 0.64, and 0.67, respectively. The AUC for the NLR, WBC, and CRP for positive blood culture was 0.76, 0.64, and 0.61, respectively; the NLR had greater power to predict disease severity, shock, and positive blood culture. The optimal cut-off value of the baseline NLR for the prediction of severe acute cholangitis, shock, and positive blood culture was 15.24 (sensitivity, 85%; specificity, 79%), 15.54 (sensitivity, 80%; specificity, 73%), and 12.35 (sensitivity, 72%; specificity, 70%), respectively. The sequential NLR values from admission to 2 days after admission were significantly higher in patients with severe cholangitis and shock. Conclusions: An elevated NLR correlates with severe acute cholangitis, shock, and positive blood culture. Serial NLR can track the clinical course of acute cholangitis.