Crohn's disease (CD) is a chronic inflammatory disease of the gastrointestinal tract, which is partially affected by gut microbiome. This review comprising of outcomes of two studies with 57 individuals was not successful in finding the efficacy of probiotics in CD limited by poor risk of bias and unclear results.

This study focused on finding out the safety and effectiveness of probiotics for initiation of remission in CD.

Embase, MEDLINE, the Cochrane, WHO International Clinical Trials Registry, and ClinicalTrials.gov database were explored from beginning. Inclusion criteria comprised of randomised controlled trials evaluating probiotics with placebo or any other non-probiotic intervention regarding initiation of remission in CD. Data extraction and methodological quality of studies was assessed indivisually by 2 reviewers. Clinical remission was regarded as the primary outcome. The risk ratios (RRs) and 95% confidence intervals (CIs) were deliberated for dichotomous outcomes.

Two studies met the inclusion criteria. In one study, 11 individuals with varing degree of CD on a week course of corticosteroids and antibiotics (ciprofloxacin 500 mg bid and metronidazole 250 mg tid) treatment was considered. Thereafter, they were randomly assigned to Lactobacillus rhamnosus strain GG (2 billion colony-forming units daily) or corn starch placebo.

In the other study, 35 individuals with active CD (Clinical Disease Activity Index (CDAI) of 150 out of 450) were randomised to receive a synbiotic therapy (freeze-dried Bifidobacterium longum plus commercial produce) or placebo. One study had low risk of bias and other one had unclear risk of bias concerning arbitrary sequence generation, allocation concealment, and blinding.

After 6 months, no evidence of a disparity between probiotics use and placebo for the induction of remission in CD was found. Also, no difference in adverse events between probiotics and placebo was observed. Both outcomes had very low certainty because of risk of bias and ambiguity.

As concluded, the pooled analysis in this review found no advantage concerning the use of probiotics in CD remission.  Due to absence of well-designed RCTs, future research is awaited.