Why is Ranson's criteria (Ranson's criteria) no longer used for predicting mortality in acute pancreatitis?

From the Guidelines

Ranson's criteria is no longer widely used for predicting acute pancreatitis severity because more accurate and practical scoring systems, such as BISAP, have replaced it. The criteria required measurements at admission and again at 48 hours, making it cumbersome for rapid clinical decision-making 1. Additionally, Ranson's criteria demonstrated only moderate accuracy with sensitivity and specificity around 70-80%, whereas the BISAP score has similar accuracy to the APACHE-II score for predicting death and can be easily applied in the earliest phases 1.

Key Points

• Ranson's criteria has been largely replaced by more modern scoring systems due to its limitations in accuracy and practicality 1.
• The BISAP score is a recently developed prognostic scoring system that has been proposed as a simple method for prediction of severe acute pancreatitis, with similar accuracy to the APACHE-II score for predicting death 1.
• A retrospective analysis of 303 patients revealed that BISAP predicts severity, death, and especially organ failure in AP as well as APACHE-II does, and better than Ranson criteria, CT-severity index, CRP, hematocrit, and BMI 1.

Comparison of Scoring Systems

• The PPV for the Ranson score ranges from 28.6 to 49% (sensitivity 75–87%, specificity 68–77.5%), whereas the BISAP score has been shown to have similar accuracy to the APACHE-II score for predicting death 1.
• The APACHE II score evaluates the chronic health score and 12 physiologic measurements, but is not specific for AP and is not designed for day-to-day evaluation in any patient 1.
• The BISAP score, on the other hand, is a simplified scoring system that can be easily applied in the earliest phases and has been shown to predict severity, death, and organ failure in AP as well as APACHE-II does 1.

From the Research

Ranson's Criteria Limitations

• The Ranson score has been criticized for its 48-hour requirement for computation of the final score, which may potentially delay management 2.
• It has been argued that the Ranson score has low predictive power 2.
• Other scoring systems, such as the Bedside Index of Severity in Acute Pancreatitis (BISAP) and the Acute Physiology and Chronic Health Evaluation (APACHE) II tools, have been found to have good predictive capabilities for disease severity and mortality 3, 4.

Comparison with Other Scoring Systems

• The BISAP score has been found to be as effective as the APACHE-II score in predicting severity, death, and organ failure in acute pancreatitis, and more effective than the Ranson criteria and CT severity index (CTSI) 4.
• A study comparing different scoring systems found that the modified Glasgow score (MGS) had the highest sensitivity for predicting the severity of acute pancreatitis, while the Ranson score on admission had better diagnostic accuracy for predicting severity, organ failure, and mortality 5.
• The APACHE II score and Ranson score 48 hours after admission have been found to have fair accuracy in predicting the severity of acute pancreatitis, while the BISAP score and MGS had poor accuracy 5.

Current Usage

• Despite its limitations, the Ranson score remains widely used and has been found to consistently exhibit comparable prognostic accuracy to other newer scoring systems 2.
• The Ranson score is still considered relevant in modern clinical practice due to its relative ease of use, practicality, and universality 2.