Comparison of NLR and CRP in Identifying Organ Dysfunction-Based Severe Presentation of Acute Cholangitis in Patients with Choledocholithiasis: A Single-Center Retrospective Study

Background and Objectives: Early identification of patients at risk for severe forms of acute cholangitis (AC) is crucial for guiding prompt therapeutic interventions. In addition to traditional biomarkers such as C-reactive protein (CRP), newer indices like the neutrophil-to-lymphocyte ratio (NLR) are cost-effective and easy-to-use diagnostic tools. In the context of limited evidence from Eastern European populations, this study aimed to compare the performance of NLR and CRP in identifying organ dysfunction-based severe presentation of acute cholangitis according to a modified TG18-derived classification. Materials and Methods: We conducted a retrospective study including patients admitted to Colentina Clinical Hospital between January 2021 and September 2025. Demographic, clinical, and laboratory data were collected from medical records, with a focus on admission inflammatory biomarkers: NLR and CRP. Symptom onset-to-presentation time was not recorded. Patients were stratified by disease severity according to a modified organ dysfunction-based severity classification, and comparative statistical analysis, including Receiver Operating Characteristic (ROC) curve analysis, was performed to assess the diagnostic performance and optimal cut-off values of both biomarkers for severe clinical presentation. Results: A total of 364 patients were included, with a median age of 68 years (IQR: 60–78), and a slight female predominance (55.5%). Of these, 231 were classified as non-severe and 133 as severe. Both CRP and NLR were significantly higher in severe cases (p = 0.042 and p = 0.018, respectively. Despite statistical significance, CRP showed limited discriminatory ability, whereas NLR showed only a marginal numerical advantage. ROC analysis showed poor discriminatory ability for both CRP (AUC = 0.564, 95% CI 0.503–0.624, p = 0.042) and NLR (AUC = 0.574, 95% CI 0.513–0.635, p = 0.018) in predicting severe AC incidence. The difference between AUCs was minimal (ΔAUC = 0.010, 95% CI −0.062 to 0.082, p = 0.78, DeLong test). Conclusions: Both CRP and NLR showed limited discriminatory performance in identifying organ dysfunction-based severe presentation of acute cholangitis. The small, non-significant difference between the two markers does not support a meaningful comparative advantage, and neither biomarker appears suitable for reliable early risk stratification on its own.