Endotoxemia and Gram-negative bacteremia as predictors of outcome in sepsis: a meta-analysis using ROC curves

The prognostic value of the detection of endotoxin in plasma of patients with suspected Gram-negative sepsis is unclear despite numerous studies. Sixteen studies have reported endotoxemia detection and blood culture results with outcome data for 1937 patients with suspected Gram-negative sepsis. Comparisons of the fatality rates for the subgroups of patients with, respectively, either endotoxemia (group 3), or Gram-negative bacteremia (group 2), or both detected (group 1), versus the fatality rate for the subgroup of patients with these factors absent (group 4), were made based on summary odds ratios (and 95% CI). Summary odds ratios for the comparison of group 2 versus group 4 and group 3 versus group 4 were non-significant (2.2; 0.9-5.8 and 2.0; 0.8-4.8, respectively). The summary odds ratio was significant for group 1 versus group 4 (3.6; 2.1-6.3), and more so among studies in which non-Enterobacteriaceae were common among the Gram-negative blood culture isolates (4.8; 2.1-10.7). Endotoxemia, like Gram-negative bacteremia, is a weak prognostic indicator. Endotoxemia appears to have most prognostic significance when it is detected in the co-presence of Gram-negative bacteremia. The differing interpretations among published studies could be attributed to the variability in types of Gram-negative bacteremia observed.