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Summary
A randomized, placebo-controlled trial investigated the effects of Bifidobacterium bifidum MIMBb75 on individuals with different types of IBS, including IBS-D, IBS-C, and IBS-A. The majority of participants in the MIMBb75 probiotic group (62%) had IBS-A. At a dose of 1 billion CFU/day over 4 weeks, MIMBb75 appeared to improve symptoms of urgency, global IBS symptoms, distention/bloating, and pain/discomfort, with effect sizes ranging from moderate to strong.
However, no significant benefits were observed for bowel movement frequency or incomplete evacuation. While improvements in mental health parameters and quality of life were reported, the clinical relevance was unclear, and insufficient data was provided to calculate effect sizes for these two parameters, leading to their classification as unstudied.
Key Takeaway: Bifidobacterium bifidum MIMBb75, taken at a dose of 1 billion CFU/day for 4 weeks, may help to improve IBS symptoms such as urgency, global IBS symptoms, distention/bloating, and pain/discomfort. However, it does not seem to significantly impact bowel movement frequency or incomplete evacuation.
Dosing:
Trial Duration
Reference:
Guglielmetti S, Mora D, Gschwender M, Popp K. Randomised clinical trial: Bifidobacterium bifidum MIMBb75 significantly alleviates irritable bowel syndrome and improves quality of life – a double-blind, placebo-controlled study. Aliment Pharmacol Ther 2011; 33: 1123–32.
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Randomised clinical trial: Bifidobacterium bifidum MIMBb75 significantly alleviates irritable bowel syndrome and improves quality of life – a double-blind, placebo-controlled study
Aliment Pharmacol Ther 2011; 33: 1123–32
ADULTS
Urgency was significantly reduced by −0.67 points (95% CI: −0.86 to −0.48) in the probiotic group compared to −0.21 points (95% CI: −0.35 to −0.07) in the placebo group (p=0.0001) during treatment, but not during the wash-out phase.
A significant difference in urgency between the probiotic and placebo groups was observed between weeks 4 and 6. Baseline values for urgency were not provided.
There was no effect on bowel movement frequency in the overall population. We calculated an effect size of 0.73 for urgency, categorizing this as a moderate effect.
No effects could be detected for incomplete bowel evacuation or bowel movement frequency.
No effects were detected for bowel movement frequency.
The primary endpoint was the reduction of the Subjective Global Assessment (SGA) of IBS symptoms, measured using the subject’s global assessment diary.
Bifidobacterium bifidum MIMBb75 significantly improved global IBS symptoms by −0.88 points (95% CI: −1.07 to −0.69) (from 2.95 in the run-in phase to 2.07 in the treatment phase) compared with a reduction of only −0.16 points (95% CI: −0.32 to 0.00) (from 2.79 in the run-in phase to 2.63 in the treatment phase) in the placebo group (P < 0.0001) using the 7-point Likert scale.
This represents a 29.8% reduction in symptom score from baseline for the probiotic group, a relative therapeutic gain over placebo of 24.1%. Weekly evaluations of the SGA showed significant benefits for patients in the MIMBb75 group from the second week of treatment through the end of the study.
A composite score was calculated for the IBS symptoms pain/discomfort, distension/bloating, and urgency. Patients in the MIMBb75 group significantly benefited compared to the placebo group.
The composite score improved from 2.68 at baseline to 1.88 after treatment in the bifidobacteria group (a 29.8% improvement) and from 2.56 at baseline to 2.37 (a 7.4% improvement) in the placebo group (−0.80 in the bifidobacteria group; −0.20 in the placebo group; p < 0.0001).
This improvement was also maintained during the wash-out phase (−0.85 in the bifidobacteria group; −0.31 in the placebo group; p < 0.0001). Overall responders were defined as patients experiencing an improvement of at least 1 point on the Likert scale for the primary parameter (SGA of IBS symptoms) in at least two of the 4 weeks treatment period (50% rule).
Abdominal pain responders were similarly defined using the 50% rule for at least a one-point average improvement in ‘pain/discomfort’. The overall responder rates were 57% in the MIMBb75 group and only 21% in the placebo group (P = 0.0001). We calculated an effect size of 1.10 for global IBS symptoms, which falls in our strongest effect size range.
Bifidobacterium bifidum MIMBb75 significantly reduced pain/discomfort by −0.82 points (95% CI: −1.01 to −0.63) compared to −0.18 points (95% CI: −0.35 to −0.01) in the placebo group (p<0.0001). This reduction persisted during the wash-out phase.
Pain/discomfort responder rates were 48% in the bifidobacteria group and 24% in the placebo group (P=0.008). A responder was defined as having a ≥1-point reduction on the Likert scale for ≥2 out of 4 weeks during the treatment period.
We calculated an effect size of 0.96 for this parameter, which falls within our moderate effect size range.
Bifidobacterium bifidum MIMBb75 significantly reduced distension/bloating by -0.92 points (95% CI: −1.15 to −0.69) compared to -0.21 points (95% CI: −0.37 to −0.05) in the placebo group (p<0.0001) during the treatment.
This represented an approximate 30.5% reduction in symptom scores from baseline, providing a therapeutic gain of 23% over placebo. We independently calculated an effect size of 0.96 for this parameter, which falls within our moderate effect size range.
No data
The mental health score improved from 45.53 to 51.11 in the MIMBb75 group and from 47.01 to 48.29 in the placebo group, with changes of 5.78 and 1.58 points respectively (p=0.0083). However, these improvements were on par with typical population mean scores, raising questions about their clinical relevance.
Confidence intervals and variability measures were also not provided for this parameter, precluding our ability to independently calculate effect sizes. Therefore, we assigned this parameter as not studied.
The evaluation of SF12 sum scores indicated a significant improvement in quality of life in the MIMBb75 group.
Confidence intervals and variability measures were also not provided for this parameter, precluding our ability to independently calculate effect sizes.
Therefore, we assigned this parameter as not studied.
No subtype-specific effects were reported; however, individuals with IBS-A comprised the majority of the probiotic group (n=37; 62% of the population).
Attrition rates presented in a study figure differed significantly from those reported in the text.
Additionally, scores for mental health and quality of life were provided without confidence intervals or variability measures, preventing the calculation of effect sizes for these parameters.