Comparison of Laboratory-Based and Combined Clinical-Laboratory Models for Predicting Complicated Appendicitis: Incremental Value of the Prognostic Nutritional Index

The study compared three predictive models for identifying complicated appendicitis in 1,132 patients with acute appendicitis. Complicated appendicitis was found in 341 patients (30.1%). A laboratory-based model incorporating elevated C-reactive protein, elevated neutrophil percentage, and lower Prognostic Nutritional Index (PNI) outperformed a purely clinical model. The laboratory model achieved an AUC of 0.847, the clinical model 0.791, and the combined model 0.857. The laboratory model with PNI demonstrated comparable accuracy to the combined model while using only routinely available laboratory parameters. The findings suggest that laboratory-based models can serve as a practical adjunct to clinical assessment for early identification of complicated appendicitis.