[Artificial and bioartificial liver support systems for acute and acute-on-chronic liver failure: a meta-analysis]

To evaluate the effect of artificial and bioartificial liver support systems for management of acute and acute-on-chronic liver failure.

Articles documenting randomized clinical trials concerning any liver support systems vs standard conservative therapy, published between January, 1970 and June, 2008, were retrieved by database searching. Of the 1134 articles retrieved, 12 randomized trials involving 479 patients were included. The data were extracted and the trial quality was assessed by 2 independent reviewers. The primary outcome measure was all-cause mortality, and the results were combined on the risk ratio (RR) scale.

Of the 12 trials included, 10 assessed artificial liver support systems for acute or acute-on-chronic liver failure, and 2 assessed bioartificial systems for acute liver failure. Overall, the liver support systems had moderate effect on mortality compared with standard conservative therapy (RR=0.80; 95% CI 0.664-0.969, P=0.022). Meta-regression indicated that the effect of the support systems depended on the type of liver failure (P=0.00). In stratified meta-analyses, the support systems appeared to reduce the mortality by 43% in acute-on-chronic liver failure (RR=0.57; 95% CI 0.39-0.84, P=0.004), but not in acute liver failure (RR=0.899; 95% CI 0.72-1.12, P=0.361).

Artificial liver support systems reduce the mortality of acute-on-chronic liver failure as compared with standard conservative therapy, but have no significant effect on the mortality of acute liver failure. Bioartificial liver support systems lower the mortality rates in both acute and acute-on-chronic liver failure, and should be the future focus of development.