External validation of bloodstream infection mortality risk score in a population-based cohort.

A risk score was recently derived to predict mortality in adult patients with Gram-negative bloodstream infection ( BSI). The aim of this study was to provide external validation of the BSI mortality risk score ( BSIMRS) in a population-based cohort. All residents of Olmsted County, Minnesota, with Escherichia coli and Pseudomonas aeruginosa BSI from 1 January 1998 to 31 December 2007 were identified. Logistic regression was used to examine the association between BSIMRS and mortality. Area under receiver operating characteristic curve ( AUC) was calculated to quantify the discriminative ability of the BSIMRS to predict a variety of short-term and long-term outcomes. Overall, 424 unique Olmsted County residents with first episodes of E. coli and P. aeruginosa BSI were included in the study. Median age was 68 (range 0-99) years, 280 (66%) were women, 61 (14%) had cancer and 9 (2%) had liver cirrhosis. The BSIMRS was associated with 28-day mortality (p <0.001) with an AUC of 0.86. There was an almost 56% increase in 28-day mortality for each point increase in BSIMRS (OR 1.56, 95% CI 1.40-1.78). A BSIMRS ≥5 had a sensitivity of 74% and a specificity of 87% to predict 28-day mortality with a negative predictive value of 97%. The BSIMRS had AUC of 0.85, 0.85 and 0.81 for 7-, 14- and 365-day mortality, respectively. BSIMRS stratified mortality with high discrimination in a population-based cohort that included patients of all age groups who had a relatively low prevalence of cancer and liver cirrhosis. [ABSTRACT FROM AUTHOR]