Artificial and bioartificial support systems for acute and acute-on-chronic liver failure - A systematic review

Context Artificial and bioartificial support systems may provide a "bridge" for patients with severe liver disease to recovery or transplantation. Objective To evaluate the effect of artificial and bioartificial support systems for acute and acute-on-chronic liver failure. Data Sources Randomized trials on any support system vs standard medical therapy were included irrespective of publication status or language. Nonrandomized studies were included in explorative analyses. Trials were identified through electronic searches (Cochrane Hepato-Biliary Group Controlled Trials Register, Cochrane Library, MEDLINE, EMBASE, and the Chinese Medical Database), bibliographies, and contact with experts. Searches were conducted of the entire databases through September 2002. Study Selection Of 528 references identified, 12 randomized trials with 483 patients were included. Eight nonrandomized studies were included in explorative analyses. Data Extraction Data were extracted and trial quality was assessed independently by 3 reviewers (L.L.K., J.L., B.A-N.). The primary outcome measure was all-cause mortality. Results were combined on the risk ratio (RR) scale. Random-effects models were used. Sources of heterogeneity were explored through meta-regression and stratified meta-analyses. Data Synthesis Of the 12 trials included, 10 assessed artificial systems for acute or acute-on-chronic liver failure and 2 assessed bioartificial systems for acute liver failure. Overall, support systems had no significant effect on mortality compared with standard medical therapy (RR, 0.86; 95% confidence interval [CI], 0.65-1.12). Meta- regression indicated that the effect of support systems depended on the type of liver failure (P=.03). In stratified meta-analyses, support systems appeared to reduce mortality by 33% in acute-on-chronic liver failure (RR, 0.67; 95% CI, 0.51-0.90), but not in acute liver failure (RR, 0.95; 95% CI, 0.71-1.29). Compared with randomized trials, nonrandomized studies produced significantly larger estimates of intervention effects (P=.01). Conclusion This review suggests that artificial support systems reduce mortality in acute-on-chronic liver failure compared with standard medical therapy. Artificial and bioartificial support systems did not appear to affect mortality in acute liver failure.