Diagnostic Utility of Prognostic Nutritional Index, Systemic Immune-Inflammation Index and Related Indices for...

Acute diverticulitis is a common gastrointestinal emergency with a wide spectrum of clinical severity. The Hinchey classification, based on abdominal computed tomography (CT), remains the gold standard for staging, but timely imaging may not always be feasible in resource-limited or emergency settings. In this context, blood-derived indices may serve as useful adjuncts for early risk stratification.

This study aimed to evaluate the diagnostic utility of inflammatory and nutritional indices-including the prognostic nutritional index (PNI), systemic immune-inflammation index (SII), inflammatory prognostic index (IPI), C-reactive protein-to-albumin ratio (CAR), and CRP-albumin-lymphocyte index (CALLY)-in predicting disease severity according to the Hinchey classification.

In this retrospective cross-sectional study, 64 patients diagnosed with acute diverticulitis between 2014 and 2024 were included. All patients underwent CT-based staging and laboratory testing on admission. Receiver operating characteristic (ROC) curve analyses were performed to assess the diagnostic performance of each index across Hinchey stages 1a to 4.

PNI showed the highest accuracy in predicting Hinchey 1a [area under the curve (AUC) = 0.778, sensitivity = 80 %, specificity = 66 %]. SII demonstrated excellent performance in identifying stage 4 (AUC = 0.935), while IPI was most effective in stage 3 (AUC = 0.945). CAR and CALLY showed moderate diagnostic value in later stages.

PNI and SII may serve as practical and cost-effective tools for staging acute diverticulitis when imaging is delayed. These indices may assist in early clinical decision-making, especially in emergency and low-resource settings.