The effect of antioxidants on Helicobacter pylori eradication: A systematic review with meta-analysis.

BACKGROUND: The efficacy and safety of the addition of antioxidants to triple or quadruple therapy were unclear. MATERIALS AND METHODS: This systematic review was performed in accordance with the PRISMA 2009 guidelines. A systematic search of PubMed, EMBASE, and the Cochrane Library databases was conducted to identify potentially relevant publications using the following keywords: ([Helicobacter pylori] or [H. pylori] or [Hp]) and ([antioxidant] or [vitamin] or [N-acetylcysteine] or [curcumin] or [cranberry]). The primary end-point of this study was to evaluate the efficacy of the addition of antioxidants to triple or quadruple therapy according to ITT and PP analysis. The second end-points were side effects and the comparative efficacy in terms of H. pylori eradication according to different antioxidant and antibiotic combinations. RESULTS: We included 9 studies with 1260 participants. The total eradication rate of H. pylori in the group combining eradication therapy with antioxidants was not superior to that without antioxidants according to the ITT (pooled RR [95% CI] = 1.17 [0.99-1.38]; P = 0.07) and PP analysis (pooled RR [95% CI] = 1.15 [0.99-1.34; P = 0.07]. There were no differences regarding side effects between the two groups (pooled RR [95% CI], 1.36 [0.81-2.28]; P = 0.24). However, the eradication regimen with vitamin supplementation (1400 mg/day) showed a significant, superior efficacy in eradication relative to those without supplementation (pooled RR [95% CI] = 1.57 [1.35, 1.84]; P < 0.01). In particular, in the amoxicillin-clarithromycin-based subgroup, the crude H. pylori eradication rate determined by ITT analysis was 81.3% and 68.6% for eradication therapy with and without antioxidant supplementation, respectively, which was a statistically significant difference (pooled RR [95% CI] = 1.23 [1.02-1.49]; P = 0.03). CONCLUSIONS: The addition of antioxidants (vitamin, N-acetylcysteine, curcumin, cranberry) to amoxicillin-clarithromycin-based therapy could improve the eradication rate, and vitamin supplementation might be effective at a high dosage. However, antioxidant supplements have no impact on improving side effects.