Probiotics may benefit irritable bowel syndrome symptoms, but randomized controlled trials have been conflicting..
Dr Moayyedi and colleagues from Canada searched MEDLINE, EMBASE, and the cochrane controlled trials register electronic databases, as well as abstracts from digestive diseases week, and United European gastroenterology Week, and contacted authors for extra information.
Only parallel group randomized controlled trials with at least 1 week of treatment comparing probiotics with placebo or no treatment in adults with irritable bowel syndrome according to any acceptable definition were included.
Studies had to provide improvement in abdominal pain or global irritable bowel syndrome symptoms as an outcome.
Eligibility assessment and data extraction were performed by 2 independent researchers.
Data were synthesized using relative risk of symptoms not improving for dichotomous data and standardized mean difference for continuous data using random effects models.
|The number needed to treat with probiotic use was 4|
The researchers identified 19 randomized controlled trials in 1650 patients with irritable bowel syndrome.
Trial quality was generally good, with 9 reporting adequate methods of randomization and 6 a method of concealment of allocation.
There were 10 randomized controlled trials involving 918 patients providing outcomes as a dichotomous variable.
The research team found that probiotics were statistically significantly better than placebo with a number needed to treat equal to 4.
The research team noted significant heterogeneity and possible funnel plot asymmetry.
The researchers identified 15 trials assessing 1351 patients who reported on improvement in irritable bowel syndrome score as a continuous outcome.
There was statistically significant heterogeneity, but this was explained by one outlying trial.
Dr Moayyedi's team concluded, “Probiotics appear to be efficacious in irritable bowel syndrome, but the magnitude of benefit and the most effective species and strain are uncertain.”