Blood Urea Nitrogen in the Early Assessment of Acute Pancreatitis

BACKGROUND: Objective assessment of acute pancreatitis (AP) is critical to help guide resuscitation efforts. Herein we (1) validate serial blood urea nitrogen (BUN) measurement for early prediction of mortality and (2) develop an objective BUN-based approach to early assessment in AP. METHODS: We performed a secondary analysis of 3 prospective AP cohort studies: Brigham and Women's Hospital (BWH), June 2005 through May 2009; the Dutch Pancreatitis Study Group (DPSG), March 2004 through March 2007; and the University of Pittsburgh Medical Center (UPMC), June 2003 through September 2007. Meta-analysis and stratified multivariate logistic regression adjusted for age, sex, and creatinine levels were calculated to determine risk of mortality associated with elevated BUN level at admission and rise in BUN level at 24 hours. The accuracy of the BUN measurements was determined by area under the receiver operating characteristic curve (AUC) analysis compared with serum creatinine measurement and APACHE II score. A BUN-based assessment algorithm was derived on BWH data and validated on the DPSG and UPMC cohorts. RESULTS: A total of 1043 AP cases were included in analysis. In pooled analysis, a BUN level of 20 mg/dL or higher was associated with an odds ratio (OR) of 4.6 (95% confidence interval CI, 2.5-8.3) for mortality. Any rise in BUN level at 24 hours was associated with an OR of 4.3 (95% CI, 2.3-7.9) for death. Accuracy of serial BUN measurement (AUC, 0.82-0.91) was comparable to that of the APACHE II score (AUC, 0.72-0.92) in each of the cohorts. A BUN-based assessment algorithm identified patients at increased risk for mortality during the initial 24 hours of hospitalization. CONCLUSIONS: We have confirmed the accuracy of BUN measurement for early prediction of mortality in AP and developed an algorithm that may assist physicians in their early resuscitation efforts.