In multivariate analysis, the independent prognostic factors for death were white blood cell count (OR= 1.17; 95% CI 1.03 - 1.33), blood urea nitrogen level (OR=1.26; 95% CI 1.04 - 1.53). glomerular filtration rate (OR= 1.03; 95% CI 1 - 1.07) and surgical treatment (OR= 0.03; 95% CI 0.01 - 0.39).