Goran Bjelakovic1, Lise Lotte Gluud, Dimitrinka Nikolova, Marija Bjelakovic, Aleksandar Nagorni, Christian Gluud. 1. Cochrane Hepato-Biliary Group, Copenhagen Trial Unit, Centre for Clinical Intervention Research, Department 3344, Rigshospitalet, Copenhagen University Hospital, and Department of Internal Medicine - Gastroenterology and Hepatology, Medical Faculty, University of Nis, Zorana Djindjica 81, Nis, Serbia, 18000.
Abstract
BACKGROUND: Several liver diseases have been associated with oxidative stress. Accordingly, antioxidants have been suggested as potential therapeutics for various liver diseases. The evidence supporting these suggestions is equivocal. OBJECTIVES: To assess the benefits and harms of antioxidant supplements for patients with liver diseases. SEARCH STRATEGY: We searched The Cochrane Library, MEDLINE, EMBASE, LILACS, the Science Citation Index Expanded, and Conference Proceedings Citation Index-Science to January 2011. We scanned bibliographies of relevant publications and asked experts and pharmaceutical companies for additional trials. SELECTION CRITERIA: We considered for inclusion randomised trials that compared antioxidant supplements (beta-carotene, vitamin A, C, E, and selenium) versus placebo or no intervention for autoimmune liver diseases, viral hepatitis, alcoholic liver disease, and cirrhosis (any aetiology). DATA COLLECTION AND ANALYSIS: Four authors independently selected trials for inclusion and extracted data. Outcome measures were all-cause mortality, liver-related mortality, liver-related morbidity, biochemical indices at maximum follow-up in the individual trials as well as adverse events, quality-of-life measures, and cost-effectiveness. For patients with hepatitis B or C we also considered end of treatment and sustained virological response. We conducted random-effects and fixed-effect meta-analyses. Results were presented as relative risks (RR) or mean differences (MD), both with 95% confidence intervals (CI). MAIN RESULTS: Twenty randomised trials with 1225 participants were included. The trials assessed beta-carotene (3 trials), vitamin A (2 trials), vitamin C (9 trials), vitamin E (15 trials), and selenium (8 trials). The majority of the trials had high risk of bias and showed heterogeneity. Overall, the assessed antioxidant supplements had no significant effect on all-cause mortality (relative risk [RR] 0.84, 95% confidence interval [CI] 0.60 to 1.19, I(2) = 0%), or liver-related mortality (RR 0.89, 95% CI 0.39 to 2.05, I(2) = 37%). Stratification according to the type of liver disease did not affect noticeably the results. Antioxidant supplements significantly increased activity of gamma glutamyl transpeptidase (MD 24.21 IU/l, 95% CI 6.67 to 41.75, I(2) = 0%). AUTHORS' CONCLUSIONS: We found no evidence to support or refute antioxidant supplements in patients with liver disease. Antioxidant supplements may increase liver enzyme activity.
BACKGROUND: Several liver diseases have been associated with oxidative stress. Accordingly, antioxidants have been suggested as potential therapeutics for various liver diseases. The evidence supporting these suggestions is equivocal. OBJECTIVES: To assess the benefits and harms of antioxidant supplements for patients with liver diseases. SEARCH STRATEGY: We searched The Cochrane Library, MEDLINE, EMBASE, LILACS, the Science Citation Index Expanded, and Conference Proceedings Citation Index-Science to January 2011. We scanned bibliographies of relevant publications and asked experts and pharmaceutical companies for additional trials. SELECTION CRITERIA: We considered for inclusion randomised trials that compared antioxidant supplements (beta-carotene, vitamin A, C, E, and selenium) versus placebo or no intervention for autoimmune liver diseases, viral hepatitis, alcoholic liver disease, and cirrhosis (any aetiology). DATA COLLECTION AND ANALYSIS: Four authors independently selected trials for inclusion and extracted data. Outcome measures were all-cause mortality, liver-related mortality, liver-related morbidity, biochemical indices at maximum follow-up in the individual trials as well as adverse events, quality-of-life measures, and cost-effectiveness. For patients with hepatitis B or C we also considered end of treatment and sustained virological response. We conducted random-effects and fixed-effect meta-analyses. Results were presented as relative risks (RR) or mean differences (MD), both with 95% confidence intervals (CI). MAIN RESULTS: Twenty randomised trials with 1225 participants were included. The trials assessed beta-carotene (3 trials), vitamin A (2 trials), vitamin C (9 trials), vitamin E (15 trials), and selenium (8 trials). The majority of the trials had high risk of bias and showed heterogeneity. Overall, the assessed antioxidant supplements had no significant effect on all-cause mortality (relative risk [RR] 0.84, 95% confidence interval [CI] 0.60 to 1.19, I(2) = 0%), or liver-related mortality (RR 0.89, 95% CI 0.39 to 2.05, I(2) = 37%). Stratification according to the type of liver disease did not affect noticeably the results. Antioxidant supplements significantly increased activity of gamma glutamyl transpeptidase (MD 24.21 IU/l, 95% CI 6.67 to 41.75, I(2) = 0%). AUTHORS' CONCLUSIONS: We found no evidence to support or refute antioxidant supplements in patients with liver disease. Antioxidant supplements may increase liver enzyme activity.
Authors: G Y Lai; S J Weinstein; D Albanes; P R Taylor; J Virtamo; K A McGlynn; N D Freedman Journal: Br J Cancer Date: 2014-10-14 Impact factor: 7.640
Authors: G Y Lai; S J Weinstein; P R Taylor; K A McGlynn; J Virtamo; M H Gail; D Albanes; N D Freedman Journal: Br J Cancer Date: 2014-10-14 Impact factor: 7.640