Inflammatory Markers as Predictors of Severe Acute Pancreatitis: A Cohort Study

Background: Severe acute pancreatitis (SAP) is a clinical dilemma that is hard to diagnose early and is associated with high morbidity and mortality. There are readily accessible inflammatory markers that could help with timely and effective management and risk stratification. Purpose: The purpose of the study is to determine the predictive value of neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and C-reactive protein (CRP) in determining the severity of acute pancreatitis (AP). Methods: This retrospective multicenter cohort study included 272 adult patients admitted to two tertiary care hospitals in Pakistan (Lahore, n=142; Islamabad, n=130) with confirmed AP between September 2025 and December 2025. The revised Atlanta Criteria were used to classify the disease as severe or non-severe. Admission values were used to study the initial 24-hour values of the NLR, PLR, and CRP. Group comparisons were performed using nonparametric tests, and Spearman correlations were used; univariable logistic regression was employed to assess predictive performance given the high multicollinearity among predictors. Findings: Patients with SAP had a significantly greater median NLR when compared to those with non-SAP (Mdn 9.4 vs 4.8; U = 1026.50, p < 0.001). The median CRP was also higher among severe ones (Mdn 168mg/L vs 68mg/L; U = 1013.50, p < 0.001). NLR (r = 0.766) and CRP (r = 0.767) showed strong positive correlations with severity. A high predictive accuracy (95.2%) was observed in the study dataset, with elevated odds of severe pancreatitis associated with NLR (OR = 3.78, 95% CI: 2.83-5.06) and CRP (OR = 1.06, 95% CI: 1.05-1.08). PLR had a weak negative association with severity (0.208) and reduced predictive accuracy (74.6%). Male patients (82/155 (52.9%); χ²(1) = 10.840, p = 0.001) and patients aged 60 years and older (65/102 (63.7%); χ²(3) = 10.930, p = 0.012) had higher chances of developing severe disease. Further analyses revealed that these subgroups also exhibited significantly higher median NLR and CRP levels than those of female patients and younger patients (p < 0.05), indicating that demographic risk factors are associated with elevated inflammatory responses. Conclusion: Elevated NLR and CRP on admission were strongly associated with SAP and demonstrated higher predictive performance than PLR. These findings suggest that simple inflammatory markers may assist early risk stratification, although further prospective validation is required.