Update of the Atlanta Classification of Severity of Acute Pancreatitis: Should a Moderate Category Be Included?

Background: Persistent and multiple organ failure (POF and MOF) are predictive of death in acute pancreatitis (AP). Local complications without organ failure are associated with morbidity but a low risk of mortality. Aim: To design a three-category classification of AP severity and to compare it with the Atlanta Classification (AC) in terms of morbidity and mortality. Method: Severe AP was defined as death, POF (148 h) or MOF. Moderate AP was defined as the presence of acute collections and/or pancreatic necrosis. Mild AP was defined by exclusion. We compared this classification with AC in 144 episodes of AP. Results: In the three-category classification, severe AP was associated with significantly more frequent intensive care unit admission, invasive treatment and mortality than moderate and mild AP (p < 0.01). Severe AP patients required longer hospital stay and more nutritional support than mild AP patients (p < 0.01). Patients with moderate AP had significantly longer hospital stay and more need for nutritional support than patients with mild AP (p < 0.01). Five patients died, all of them with MOF and/or POF. Conclusions: A three-category classification distinguishes three homogeneous groups of severity.