Comparison of Laboratory-Based and Combined Clinical-Laboratory Models for Predicting Complicated Appendicitis: Incremental Value of the Prognostic Nutritional Index
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Background
Early identification of complicated appendicitis is essential for appropriate management, yet accurate preoperative risk stratification remains challenging. Whether objective laboratory-based models can achieve predictive performance comparable to models incorporating clinical findings remains unclear.
Objective
To compare clinical, laboratory-based, and combined clinical-laboratory prediction models for complicated appendicitis and to evaluate the incremental value of the Prognostic Nutritional Index (PNI).
Methods
This retrospective study included 1,132 consecutive patients with acute appendicitis. Cases were classified as uncomplicated or complicated appendicitis based on pathological findings and imaging. Three multivariable logistic regression models were developed: a clinical model (Model A), a laboratory-based model (Model B), and a combined clinical-laboratory model (Model C). Model discrimination was assessed using the area under the receiver operating characteristic curve (AUC), and AUCs were compared using DeLong’s test.
Results
Complicated appendicitis was identified in 341 patients (30.1%). Higher C-reactive protein, higher neutrophil percentage, and lower PNI were independent predictors of complicated appendicitis. The AUCs were 0.791 for Model A, 0.847 for Model B, and 0.857 for Model C. Model B significantly outperformed Model A ( P = 0.0020), whereas no significant difference was observed between Models B and C ( P = 0.0816). PNI remained an independent predictor after adjustment for conventional inflammatory markers.
Conclusion
A laboratory-based prediction model incorporating PNI demonstrated discrimination comparable to that of a combined clinical-laboratory model while relying exclusively on routinely available objective laboratory parameters. These findings support laboratory-based risk stratification as a practical adjunct to clinical assessment for the early identification of complicated appendicitis.
Article Summary
Why is this topic important?
Early identification of complicated appendicitis is essential for timely surgical decision-making and appropriate resource utilization. However, the optimal balance between predictive performance and practical implementation of preoperative risk models remains uncertain.
What does this study attempt to show?
This study compared clinical, laboratory-based, and combined clinical-laboratory prediction models for complicated appendicitis and evaluated the incremental value of the Prognostic Nutritional Index (PNI). It also assessed whether an objective laboratory-based model could achieve predictive performance comparable to that of a combined clinical-laboratory model.
What are the key findings?
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A laboratory-based model incorporating PNI demonstrated discrimination comparable to that of the combined clinical-laboratory model.
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PNI remained an independent predictor after adjustment for conventional inflammatory markers.
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The combined model achieved the best overall predictive performance, whereas the laboratory-based model offered greater simplicity and potential for standardized implementation.
How is patient care impacted?
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Objective laboratory-based risk stratification may support early identification of patients at high risk for complicated appendicitis.
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A laboratory-based model may be particularly useful in settings where advanced imaging is limited or ultrasonography expertise is unavailable.
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Routine laboratory data may facilitate standardized preoperative risk assessment and clinical decision-making.
