Predicting Prolonged Length of Stay in Acute Pancreatitis: Comparison of the CRP-to-Albumin Ratio with Other Inflammatory and Immunoutritional Indices

Objective: Due to the varied clinical manifestations of acute pancreatitis (AP), prompt identification of patients predisposed to extended hospitalization is essential for efficient resource allocation. This study assessed the predictive efficacy of inflammatory and immunonutritional ratios—namely, C-reactive protein/albumin ratio (CAR), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and hemoglobin, albumin, lymphocyte, and platelet score (HALP)—in predicting hospitalizations lasting more than 7 days. Methods: A retrospective cohort analysis was performed on 306 patients treated at a tertiary center from June 2020 to June 2025. We used Mann–Whitney U tests, ROC analysis, and multivariate logistic regression models to evaluate the relationship between admission laboratory-derived ratios and length of stay. Results: In total, 27.5% (n = 84) of the cohort experienced prolonged hospitalization. Individual markers exhibited moderate discrimination; however, procalcitonin and CAR displayed high negative predictive values (>85%), demonstrating clinical utility in excluding prolonged hospital stays. Multivariate analysis revealed advanced age (p < 0.001) and increased CAR (p < 0.001) as the most significant independent predictors. On the other hand, the HALP score was much lower in the group that stayed longer, but it was not an independent predictor in the multivariate model. Conclusions: Older age and a higher CAR are both independent factors that can predict longer hospital stays in AP. The high negative predictive value of CAR is important because it represents a reliable way to exclude prolonged hospitalization. Low CAR levels at admission may help clinicians identify patients eligible for early discharge, thereby optimizing bed management.