Background: Alcohol is a major cause of liver disease and disrupts methionine and oxidative balances. S-adenosyl-L-methionine (SAMe) acts as a methyl donor for methylation reactions and participates in the synthesis of glutathione, the main cellular antioxidant. Randomised clinical trials have addressed the question whether SAMe may benefit patients with alcoholic liver diseases.
Objectives: To evaluate the beneficial and harmful effects of SAMe for patients with alcoholic liver diseases.
Search strategy: We searched The Cochrane Hepato-Biliary Group Controlled Trials Register (May 2005), The Cochrane Central Register of Controlled Trials in The Cochrane Library (Issue 2, 2005), MEDLINE (1950 to May 2005), EMBASE (1980 to May 2005), and Science Citation Index Expanded (searched May 2005).
Selection criteria: We included randomised clinical trials studying patients with alcoholic liver diseases. Interventions encompassed per oral or parenteral administration of SAMe at any dose versus placebo or no intervention.
Data collection and analysis: We performed all analyses according to the intention-to-treat method using RevMan Analyses provided by the Cochrane Collaboration. We evaluated the methodological quality of the randomised clinical trials by quality components.
Main results: We identified nine randomised clinical trials including a heterogeneous sample of 434 patients with alcoholic liver diseases. The methodological quality regarding randomisation was generally low, but 8 out of 9 trials were placebo controlled. Only one trial including 123 patients with alcoholic cirrhosis used adequate methodology and reported clearly on all-cause mortality and liver transplantation. We found no significant effects of SAMe on all-cause mortality (relative risks (RR) 0.62, 95% confidence interval (CI) 0.30 to 1.26), liver-related mortality (RR 0.68, 95% CI 0.31 to 1.48), all-cause mortality or liver transplantation (RR 0.55; 95% CI 0.27 to 1.09), or complications (RR 1.35, 95% CI 0.84 to 2.16), but the analysis is based mostly on one trial only. SAMe was not significantly associated with non-serious adverse events (RR 4.92; 95% CI 0.59 to 40.89) and no serious adverse events were reported.
Authors' conclusions: We could not find evidence supporting or refuting the use of SAMe for patients with alcoholic liver diseases. We need more long-term, high-quality randomised trials on SAMe for these patients before SAMe may be recommended for clinical practice.