Ten trials were included (n=963 participants); two double-blind randomised controlled trials (RCTs), two single-blind RCTs, one double-blind quasi-RCT, two unblinded quasi RCTs and three quasi RCTs with unclear blinding (n not available for individual studies). Six of the trials were placebo-controlled. Allocation concealment was deemed adequate in only one trial, unclear in six trials and inadequate in three trials. Loss to follow-up was less than 5% in six trials, between 5% to 9% in three trials, and 10% or more in one trial.
Eradication rates: Significantly more patients treated with fermented milk-based probiotic preparations achieved Helicobacter eradication compared to controls (odds ratio 1.91, 95% CI: 1.38 to 2.65; nine trials, n=943 participants) and eradication rates improved by approximately 10% with the use of fermented milk-based probiotics (risk difference 0.10, 95% CI: 0.05, 0.15; ten trials, n=963 participants).
Change in C-urea breath test values: Fermented milk probiotic supplements were associated with a greater reduction in C-urea breath test values compared to controls (standardised mean difference -0.46, 95% CI: -0.73, -0.20; three trials, n=227 participants). There was no significant difference between groups in the incidence of adverse events (six trials, n=719 participants).
There was no evidence of statistically significant heterogeneity or publication bias for any of the findings. Sensitivity analyses and per-protocol analyses did not alter the findings significantly. Univariate meta-regression analyses did not reveal any significant effect of trial quality, bacterial preparation, duration of supplement, co-intervention or age group on outcomes.