UC Irvine

Objective

Lipopolysaccharide or endotoxin constitutes most part of the outer portion of the cell wall in the gram-negative bacteria. Subclinical endotoxemia could contribute to increased inflammation and mortality in hemodialysis (HD) patients. Endotoxin level and clinical effect are determined by its soluble receptor sCD14 and high-density lipoprotein. We examine the hypothesis that endotoxin level correlates with mortality.

Methods

In this cohort study, endotoxin levels were measured in 306 long-term HD patients who were then followed up for a maximum of 42 months. Soluble CD14 and cytokines levels were also measured.

Results

The mean (±SD) endotoxin level was 2.31 ± 3.10 EU/mL (minimum: 0.26 EU/mL, maximum: 22.94 EU/mL, interquartile range: 1.33 EU/mL, median: 1.27 EU/mL). Endotoxin correlated with C-reactive protein (r = 0.11, P < .04). On multivariate logistic regression analysis, high body mass index and low high-density lipoprotein (HDL) cholesterol levels were associated with higher endotoxemia (endotoxin below or above of median). In multivariate Cox regression analysis adjusted for case-mix and nutritional/inflammatory confounders, endotoxin levels in the third quartile versus first quartile were associated with a trend toward increased hazard ratio for death (hazard ratio: 1.83, 95% confidence interval: 0.93 to 3.6, P = .08).

Conclusions

In this HD cohort, we found associations between endotoxemia and C-reactive protein, body composition, and HDL. Moderately high endotoxin levels tended to correlate with increased mortality than the highest circulating endotoxin level. Additional studies are required to assess the effect of endotoxemia on mortality in dialysis population.