Comparison of BISAP, Ranson's, APACHE-II, and CTSI scores in predicting organ failure, complications, and mortality in acute pancreatitis.

Objectives: Identification of patients at risk for severe disease early in the course of acute pancreatitis (AP) is an important step to guiding management and improving outcomes. A new prognostic scoring system, the bedside index for severity in AP (BISAP), has been proposed as an accurate method for early identification of patients at risk for in-hospital mortality. The aim of this study was to compare BISAP (blood urea nitrogen >25 mg/dl, impaired mental status, systemic inflammatory response syndrome (SIRS), age>60 years, and pleural effusions) with the "traditional" multifactorial scoring systems: Ranson's, Acute Physiology and Chronic Health Examination (APACHE)-II, and computed tomography severity index (CTSI) in predicting severity, pancreatic necrosis (PNec), and mortality in a prospective cohort of patients with AP.

Methods: Extensive demographic, radiographic, and laboratory data from consecutive patients with AP admitted or transferred to our institution was collected between June 2003 and September 2007. The BISAP and APACHE-II scores were calculated using data from the first 24 h from admission. Predictive accuracy of the scoring systems was measured by the area under the receiver-operating curve (AUC).

Results: There were 185 patients with AP (mean age 51.7, 51% males), of which 73% underwent contrast-enhanced CT scan. Forty patients developed organ failure and were classified as severe AP (SAP; 22%). Thirty-six developed PNec (19%), and 7 died (mortality 3.8%). The number of patients with a BISAP score of > or =3 was 26; Ranson's > or =3 was 47, APACHE-II > or =8 was 66, and CTSI > or =3 was 59. Of the seven patients that died, one had a BISAP score of 1, two had a score of 2, and four had a score of 3. AUCs for BISAP, Ranson's, APACHE-II, and CTSI in predicting SAP are 0.81 (confidence interval (CI) 0.74-0.87), 0.94 (CI 0.89-0.97), 0.78 (CI 0.71-0.84), and 0.84 (CI 0.76-0.89), respectively.

Conclusions: We confirmed that the BISAP score is an accurate means for risk stratification in patients with AP. Its components are clinically relevant and easy to obtain. The prognostic accuracy of BISAP is similar to those of the other scoring systems. We conclude that simple scoring systems may have reached their maximal utility and novel models are needed to further improve predictive accuracy.