Neutrophil-C-reactive protein index as a novel prognostic tool for acute pancreatitis in resource-constrained settings

Background: Acute pancreatitis (AP) requires early risk stratification, particularly in resource-limited settings. This study evaluates the Neutrophil × C-Reactive Protein Index (NCI) as a biomarker for predicting severe acute pancreatitis (SAP) and in-hospital mortality. Methods: In this prospective cohort study, adult AP patients were enrolled consecutively at a tertiary hospital in Vietnam. Complete blood count and C-reactive protein (CRP) levels were measured within 24 hours of admission. NCI was compared against other neutrophil-lymphocyte-CRP combinations and the Bedside Index for Severity in Acute Pancreatitis (BISAP). Prognostic performance was assessed using the area under the receiver operating characteristic curves (AUCs), and a Restricted Cubic Splines analysis explored the linear relationship between NCI and SAP risk. Internal and external validations were performed. Results: The study included 257, 83, and 121 patients in the training, internal, and external cohorts, respectively. Optimal NCI cut-off values were ≥1877 for SAP and ≥3180 for mortality. NCI showed a linear relationship with SAP risk (p-values for non-linearity: 0.420–0.773). NCI predicted SAP with AUCs of 0.853, 0.897, and 0.844 across cohorts. It outperformed CLR (AUCs 0.653–0.856) and NLR (AUCs 0.719–0.844), with performance similar to NCLR (AUCs 0.832–0.898). For in-hospital mortality, NCI achieved AUCs of 0.824–0.902, comparable to BISAP (0.735–0.943), and outperformed other combinations. Good calibration and clinically relevant post-test probabilities were observed. Conclusions: NCI is a simple, accessible, and effective biomarker for early risk stratification in SAP and in-hospital mortality, particularly in resource-limited settings. Its reliance on routine blood tests supports its practical use for timely triage and management of AP.