A Cochrane review [Abstract] 1 included 10 studies with a total of 1015 patients. Generally the studies were poorly designed, and underpowered, with low numbers of participants and of short duration. Four studies were included in a meta-analysis of the predetermined primary outcome measure, survival at 12 months treatment. No significant effect was observed all antioxidants combined. In the individual studies no significant effect was observed for vitamin E 500 mg twice daily; vitamin E 1 g five times daily; acetylcysteine 50 mg/kg daily subcutaneous infusion; or a combination of L-methionine 2 g, vitamin E 400 IU, and selenium 3 × 10-5g three times daily (Alsemet). No significant differences were demonstrated in any of the secondary outcome measures. The antioxidants were generally well tolerated.
Comment: The quality of evidence is downgraded by limitations in study quality (e.g. inadequate follow up), by imprecise results (limited study size for each comparison) and by inconsistency (heterogeneity in interventions and outcomes).
Primary/Secondary Keywords