Reviewer's report
Title:Effectiveness of a probiotic 'functional food' in the management of irritable
bowel syndrome: A randomized controlled trial
Version: 1Date:6 November 2012
Reviewer: Filippo Cremonini
Reviewer's report:
Roberts and colleagues report the results of a 4-week multi-center RCT of
probiotic-supplemented daily yoghurt versus yoghurt alone in 179 patients with
IBS classified by Rome III criteria. The strains used were B.lactis CNCM I-2494,
S.termophilus and L.bulgaricus. The Authors report essentially no association of
symptom improvement according to treatment groups. This study attests to an
effort of transparency in submitting for publication negative results in a field which
is affected by publication bias.
I have the following comments
-The attrition rate in the run-in phase ended up limiting the sample size to the
point that this study might actually be underpowered.
-The use of a ‘base’ product that contains some lactose is not ideal when dealing
with a patient population in which diarrhea and/or underlying greater prevalence
of lactose intolerance are present -The recruitment of patients with all bowel habit
sub-categories further impacts the limitations in power and the interpretation of
data. However, this is common to most probiotic studies in IBS -Consequently to
the previous point, the use of global improvement as primary endpoint is not the
most desirable to interpret data, but the only one applicable given the ‘mixed bag’
population. Please explain why the primary endpoint was week 4 rather than end
or treatment -Has fecal recovery of the product administered been tested before?
And resistance to acid and bile?
-Overall, I do not fully agree that these results are in variance with most of the
literature. A careful assessment of results from most probiotic trials in IBS would
support marginal efficacy at best, despite the positive estimates of pooled effects
from meta-analyses combining several smaller studies with significant
heterogeneity
Reviewer's report
Title:Effectiveness of a probiotic 'functional food' in the management of irritable
bowel syndrome: A randomized controlled trial
Version: 1Date:6 November 2012
Reviewer: Filippo Cremonini
Reviewer's report:
Roberts and colleagues report the results of a 4-week multi-center RCT of
probiotic-supplemented daily yoghurt versus yoghurt alone in 179 patients with
IBS classified by Rome III criteria. The strains used were B.lactis CNCM I-2494,
S.termophilus and L.bulgaricus. The Authors report essentially no association of
symptom improvement according to treatment groups. This study attests to an
effort of transparency in submitting for publication negative results in a field which
is affected by publication bias.
I have the following comments
-The attrition rate in the run-in phase ended up limiting the sample size to the
point that this study might actually be underpowered.
-The use of a ‘base’ product that contains some lactose is not ideal when dealing
with a patient population in which diarrhea and/or underlying greater prevalence
of lactose intolerance are present -The recruitment of patients with all bowel habit
sub-categories further impacts the limitations in power and the interpretation of
data. However, this is common to most probiotic studies in IBS -Consequently to
the previous point, the use of global improvement as primary endpoint is not the
most desirable to interpret data, but the only one applicable given the ‘mixed bag’
population. Please explain why the primary endpoint was week 4 rather than end
or treatment -Has fecal recovery of the product administered been tested before?
And resistance to acid and bile?
-Overall, I do not fully agree that these results are in variance with most of the
literature. A careful assessment of results from most probiotic trials in IBS would
support marginal efficacy at best, despite the positive estimates of pooled effects
from meta-analyses combining several smaller studies with significant
heterogeneity
Please review this paper.
user
Reviewer's report
Title:Effectiveness of a probiotic 'functional food' in the management of irritable
bowel syndrome: A randomized controlled trial
Version: 1Date:6 November 2012
Reviewer: Filippo Cremonini
Reviewer's report:
Roberts and colleagues report the results of a 4-week multi-center RCT of
probiotic-supplemented daily yoghurt versus yoghurt alone in 179 patients with
IBS classified by Rome III criteria. The strains used were B.lactis CNCM I-2494,
S.termophilus and L.bulgaricus. The Authors report essentially no association of
symptom improvement according to treatment groups. This study attests to an
effort of transparency in submitting for publication negative results in a field which
is affected by publication bias.
I have the following comments
-The attrition rate in the run-in phase ended up limiting the sample size to the
point that this study might actually be underpowered.
-The use of a ‘base’ product that contains some lactose is not ideal when dealing
with a patient population in which diarrhea and/or underlying greater prevalence
of lactose intolerance are present -The recruitment of patients with all bowel habit
sub-categories further impacts the limitations in power and the interpretation of
data. However, this is common to most probiotic studies in IBS -Consequently to
the previous point, the use of global improvement as primary endpoint is not the
most desirable to interpret data, but the only one applicable given the ‘mixed bag’
population. Please explain why the primary endpoint was week 4 rather than end
or treatment -Has fecal recovery of the product administered been tested before?
And resistance to acid and bile?
-Overall, I do not fully agree that these results are in variance with most of the
literature. A careful assessment of results from most probiotic trials in IBS would
support marginal efficacy at best, despite the positive estimates of pooled effects
from meta-analyses combining several smaller studies with significant
heterogeneity
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