Background & aim: We aimed to evaluate the efficacy and safety of probiotics and synbiotics in childhood functional constipation.

Methods: PubMed, Embase, Cochrane Library, ClinicalTrials.gov, and the International Clinical Trials Registry Platform (ICTRP) were searched up to June 2023. Randomized controlled trials involving children diagnosed with FC with Rome III/IV criteria were included. Treatment success, defecation frequency, stool consistency, painful defecation, fecal incontinence, and adverse events were assessed as outcomes. Odds ratios (ORs) and standard mean difference (SMD) with 95% confidence intervals (CIs) were calculated for dichotomous and continuous variables as appropriate. Cochrane risk-of-bias tool version 2 assessed the risk of bias.

Results: Seventeen RCTs with 1504 patients were included. Compared to placebo, probiotics significantly improved defecation frequency (SMD 0.40, 95% CI 0.10 to 0.70, I² = 0%) and fecal incontinence (OR 0.53, 95% CI 0.29 to 0.96, I² = 0%). However, it did not significantly improve treatment success, painful defecation, and abdominal pain. Probiotics, as add-on therapy, failed to yield a significant difference in treatment success (OR 0.82, 95% CI 0.15 to 4.48, I² = 52%), defecation frequency (SMD 0.13, 95% CI -0.13 to 0.39, I² = 0%), defecation consistency (SMD -0.01, 95% CI -0.40 to 0.38, I² = 1%), fecal incontinence (OR 0.95, 95% CI 0.48 to 1.90, I² = 0%), and abdominal pain (OR, 0.60, 95% CI 0.24 to 1.53, I² = 0%) versus laxatives monotherapy. Synbiotics plus laxatives showed no significant effect on defecation frequency (SMD -0.57; 95% CI -1.29 to 0.14, I² = 74%) and painful defecation (OR, 3.39; 95% CI 0.74 to 15.55, I² = 0%) versus laxatives alone.

Conclusions: Current evidence did not advocate using probiotics and synbiotics in treating functional constipation in children. At this time, the effects of strain-specific probiotics, probiotics mixtures, and the optimal doses and treatment durations of the probiotics and synbiotics were unclear. Additional rigorous evidence is required to evaluate and establish the effectiveness and safety of probiotics and synbiotics for childhood functional constipation.

Prospero id: CRD42020195869.