Reviewer ’s report  
 
Title: Addition of Lubiprostone to polyethylene glycol(PEG) enhances the quality & efficacy of 
colonoscopy preparation: A randomized, double -blind, placebo controlled trial  
 
Version: 0 Date: 14 Jan 2016  
 
Reviewer: James  Tabibian  
 
Reviewer's report:  
 
In this single center, double -blind, placebo -controlled trial, the authors aimed to evaluate 
lubiprostone as an a djuvant colon preparation agent in patients scheduled to undergo 
colonoscopy. This is a large study of an important topic, and the effort by this group of highly 
skilled and esteemed investigators is laudable.  There are no major issues with the manuscript , 
and no changes that should be insurmountable.  Perhaps the biggest issue is the readability due to 
a number of writing errors of various types.  Therefore, while the science is not jeopardized, at 
times the manuscript is difficult to satisfactorily under stand and thus needs revision.  
 
 
Specific points that should be considered, the majority of which are quite minor, are as follows:  
 
 
 
 
Title:  
 
-Could the authors shorten the title?  
 
 
-“placebo controlled” should be hyphenated -There needs to be a space between a 
word/expression and its abbreviation, including but not limited to “Polyethylene glycol(PEG)”  
 
 
 
 
Abstract:  
 
-The phrase “Single center prospective double blind randomized controlled trial” needs proper 
punctuation.  
 
 
-Would select a different expression instead  of “Phase”, perhaps “part”.  “Phase I” for example 
suggests a dose finding clinical study, which I don’t think was the goal of this RCT.  
 
-Were the patients studied herein referred for screening colonoscopy only or a mixture of 
screening and diagnostic, th erapeutic, etc.?  
 
 
-It’s unclear from the wording if by “BBPS -9: excellent and BBPS 0 -4: repeat procedure” the 
authors are trying to describe the Boston score if they’re describing their methodology as to in 
what circumstances (i.e. what score ranges) they c onsider repeat colonoscopy necessary.  
Clarification would be helpful.  
 
 
-Last sentence, the authors might consider revising to something along the lines of, “When 
combined with LB, there was no significant difference in quality of preparation with 1L of PEG  
compared to 1.5 L.  
 
 
 
Keywords:  
 
-Consider using different keywords than those already included in the title of the manuscript (to 
enhance searchability and highlight the authors’ work).  
 
 
 
 
Introduction:  
 
-The following sentence is quite long and lacks proper punctuation (e.g. commas), as a result of 
which it is difficult for the reader: “Lubiprostone (LB) is a locally acting selective Type 2 
chloride channel activator which causes intestinal fluid secretio n resulting in increased softened 
stool and increased intestinal transit without the loss of either net intravascular fluid or 
electrolytes”  Similar issue with “Accordingly we conducted this prospective double blinded 
randomized placebo controlled trial w ith the primary objective to evaluate the efficacy of 
standard PEG preparation with the addition of single dose LB (24mcg) vs a placebo 
preparation.”.  
 
 
-Several words/expressions in the manuscript are misspelled or underpunctuated, including but 
not limited  to “vis a vis”.  This should be corrected to which should be “vis -à-vis”, or a different 
expression should be used, e.g. “compared to”.  
 
 
 
 
Methods:  
 
-No concerns other than those mentioned above that relate to methods.  
Results:  
 
-No concerns other than those  mentioned above that relate to methods.  
 
 
 
 
Discussion:  
 
-There seems to be partial inadvertent duplication” This study addresses two important issues 
relevant to bowel preparation: a) the quality of preparation & b) the reduced PEG dosage needed 
for adequate  preparation.  
 
This study addresses three important issues relevant to bowel preparation: a) the quality of 
preparation b) the reduced PEG dosage needed for adequate preparation & c) effective same day 
preparation”.  
 
 
-How does the cost of lubiprostone compar e to bisacodyl?  The former is likely at least an order 
of magnitude more expensive and may be more difficult to gain access to, at least in the USA.  
This should be discussed.  
 
 
-The discussion is poorly organized.  For example, there are at least 16 separa te paragraphs; this 
should be more streamlined and better flowing.  
 
 
Tables and Figures are not seen in the PDF file.  
 
 
 
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
No 
 
Does the work i nclude the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
Yes 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
Yes 
Are you able to assess any statistics in the manuscript or would you recommend an  
additional statistical review?  
If an additional statistical review is recommended, please specify what aspects require further  
assessment in your comments to the editors.  
 
I am able to assess the statistics  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Not suitable for publication unless extensively edited  
 
 
 
 
Declaration of competing interests  
Please complete a declaration of competing inter ests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an  
organisation that may in any way gain or lose financially from the publication of this  
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose  
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the  
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds  or has applied for patents relating to the content of the manuscript?  
 
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare that I have no competing interests' 
below.  If you r reply is yes to any, please give details below.  
 
I declare that I have no competing interests  
  
I agree to the open peer review policy of the journal. I understand that my name will be included  
on my report to the authors and, if the manuscript is accepte d for publication, my named report  
including any attachments I upload will be posted on the website along with the authors'  
responses. I agree for my report to be made available under a n Open Access Creative Commons  
CC-BY license ( http://creativecommons.or g/licenses/by/4.0/ ). I understand that any comments  
which I do not wish to be included in my named report can be included as confidential comments  
to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal  
Reviewer ’s report  
 
Title: Addition of Lubiprostone to polyethylene glycol(PEG) enhances the quality & efficacy of 
colonoscopy preparation: A randomized, double -blind, placebo controlled trial  
 
Version: 0 Date: 14 Jan 2016  
 
Reviewer: James  Tabibian  
 
Reviewer's report:  
 
In this single center, double -blind, placebo -controlled trial, the authors aimed to evaluate 
lubiprostone as an a djuvant colon preparation agent in patients scheduled to undergo 
colonoscopy. This is a large study of an important topic, and the effort by this group of highly 
skilled and esteemed investigators is laudable.  There are no major issues with the manuscript , 
and no changes that should be insurmountable.  Perhaps the biggest issue is the readability due to 
a number of writing errors of various types.  Therefore, while the science is not jeopardized, at 
times the manuscript is difficult to satisfactorily under stand and thus needs revision.  
 
 
Specific points that should be considered, the majority of which are quite minor, are as follows:  
 
 
 
 
Title:  
 
-Could the authors shorten the title?  
 
 
-“placebo controlled” should be hyphenated -There needs to be a space between a 
word/expression and its abbreviation, including but not limited to “Polyethylene glycol(PEG)”  
 
 
 
 
Abstract:  
 
-The phrase “Single center prospective double blind randomized controlled trial” needs proper 
punctuation.  
 
 
-Would select a different expression instead  of “Phase”, perhaps “part”.  “Phase I” for example 
suggests a dose finding clinical study, which I don’t think was the goal of this RCT.  
 
-Were the patients studied herein referred for screening colonoscopy only or a mixture of 
screening and diagnostic, th erapeutic, etc.?  
 
 
-It’s unclear from the wording if by “BBPS -9: excellent and BBPS 0 -4: repeat procedure” the 
authors are trying to describe the Boston score if they’re describing their methodology as to in 
what circumstances (i.e. what score ranges) they c onsider repeat colonoscopy necessary.  
Clarification would be helpful.  
 
 
-Last sentence, the authors might consider revising to something along the lines of, “When 
combined with LB, there was no significant difference in quality of preparation with 1L of PEG  
compared to 1.5 L.  
 
 
 
Keywords:  
 
-Consider using different keywords than those already included in the title of the manuscript (to 
enhance searchability and highlight the authors’ work).  
 
 
 
 
Introduction:  
 
-The following sentence is quite long and lacks proper punctuation (e.g. commas), as a result of 
which it is difficult for the reader: “Lubiprostone (LB) is a locally acting selective Type 2 
chloride channel activator which causes intestinal fluid secretio n resulting in increased softened 
stool and increased intestinal transit without the loss of either net intravascular fluid or 
electrolytes”  Similar issue with “Accordingly we conducted this prospective double blinded 
randomized placebo controlled trial w ith the primary objective to evaluate the efficacy of 
standard PEG preparation with the addition of single dose LB (24mcg) vs a placebo 
preparation.”.  
 
 
-Several words/expressions in the manuscript are misspelled or underpunctuated, including but 
not limited  to “vis a vis”.  This should be corrected to which should be “vis -à-vis”, or a different 
expression should be used, e.g. “compared to”.  
 
 
 
 
Methods:  
 
-No concerns other than those mentioned above that relate to methods.  
Results:  
 
-No concerns other than those  mentioned above that relate to methods.  
 
 
 
 
Discussion:  
 
-There seems to be partial inadvertent duplication” This study addresses two important issues 
relevant to bowel preparation: a) the quality of preparation & b) the reduced PEG dosage needed 
for adequate  preparation.  
 
This study addresses three important issues relevant to bowel preparation: a) the quality of 
preparation b) the reduced PEG dosage needed for adequate preparation & c) effective same day 
preparation”.  
 
 
-How does the cost of lubiprostone compar e to bisacodyl?  The former is likely at least an order 
of magnitude more expensive and may be more difficult to gain access to, at least in the USA.  
This should be discussed.  
 
 
-The discussion is poorly organized.  For example, there are at least 16 separa te paragraphs; this 
should be more streamlined and better flowing.  
 
 
Tables and Figures are not seen in the PDF file.  
 
 
 
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
No 
 
Does the work i nclude the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
Yes 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
Yes 
Are you able to assess any statistics in the manuscript or would you recommend an  
additional statistical review?  
If an additional statistical review is recommended, please specify what aspects require further  
assessment in your comments to the editors.  
 
I am able to assess the statistics  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Not suitable for publication unless extensively edited  
 
 
 
 
Declaration of competing interests  
Please complete a declaration of competing inter ests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an  
organisation that may in any way gain or lose financially from the publication of this  
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose  
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the  
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds  or has applied for patents relating to the content of the manuscript?  
 
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare that I have no competing interests' 
below.  If you r reply is yes to any, please give details below.  
 
I declare that I have no competing interests  
  
I agree to the open peer review policy of the journal. I understand that my name will be included  
on my report to the authors and, if the manuscript is accepte d for publication, my named report  
including any attachments I upload will be posted on the website along with the authors'  
responses. I agree for my report to be made available under a n Open Access Creative Commons  
CC-BY license ( http://creativecommons.or g/licenses/by/4.0/ ). I understand that any comments  
which I do not wish to be included in my named report can be included as confidential comments  
to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal  
Please review this paper.
user
Reviewer ’s report  
 
Title: Addition of Lubiprostone to polyethylene glycol(PEG) enhances the quality & efficacy of 
colonoscopy preparation: A randomized, double -blind, placebo controlled trial  
 
Version: 0 Date: 14 Jan 2016  
 
Reviewer: James  Tabibian  
 
Reviewer's report:  
 
In this single center, double -blind, placebo -controlled trial, the authors aimed to evaluate 
lubiprostone as an a djuvant colon preparation agent in patients scheduled to undergo 
colonoscopy. This is a large study of an important topic, and the effort by this group of highly 
skilled and esteemed investigators is laudable.  There are no major issues with the manuscript , 
and no changes that should be insurmountable.  Perhaps the biggest issue is the readability due to 
a number of writing errors of various types.  Therefore, while the science is not jeopardized, at 
times the manuscript is difficult to satisfactorily under stand and thus needs revision.  
 
 
Specific points that should be considered, the majority of which are quite minor, are as follows:  
 
 
 
 
Title:  
 
-Could the authors shorten the title?  
 
 
-“placebo controlled” should be hyphenated -There needs to be a space between a 
word/expression and its abbreviation, including but not limited to “Polyethylene glycol(PEG)”  
 
 
 
 
Abstract:  
 
-The phrase “Single center prospective double blind randomized controlled trial” needs proper 
punctuation.  
 
 
-Would select a different expression instead  of “Phase”, perhaps “part”.  “Phase I” for example 
suggests a dose finding clinical study, which I don’t think was the goal of this RCT.  
 
-Were the patients studied herein referred for screening colonoscopy only or a mixture of 
screening and diagnostic, th erapeutic, etc.?  
 
 
-It’s unclear from the wording if by “BBPS -9: excellent and BBPS 0 -4: repeat procedure” the 
authors are trying to describe the Boston score if they’re describing their methodology as to in 
what circumstances (i.e. what score ranges) they c onsider repeat colonoscopy necessary.  
Clarification would be helpful.  
 
 
-Last sentence, the authors might consider revising to something along the lines of, “When 
combined with LB, there was no significant difference in quality of preparation with 1L of PEG  
compared to 1.5 L.  
 
 
 
Keywords:  
 
-Consider using different keywords than those already included in the title of the manuscript (to 
enhance searchability and highlight the authors’ work).  
 
 
 
 
Introduction:  
 
-The following sentence is quite long and lacks proper punctuation (e.g. commas), as a result of 
which it is difficult for the reader: “Lubiprostone (LB) is a locally acting selective Type 2 
chloride channel activator which causes intestinal fluid secretio n resulting in increased softened 
stool and increased intestinal transit without the loss of either net intravascular fluid or 
electrolytes”  Similar issue with “Accordingly we conducted this prospective double blinded 
randomized placebo controlled trial w ith the primary objective to evaluate the efficacy of 
standard PEG preparation with the addition of single dose LB (24mcg) vs a placebo 
preparation.”.  
 
 
-Several words/expressions in the manuscript are misspelled or underpunctuated, including but 
not limited  to “vis a vis”.  This should be corrected to which should be “vis -à-vis”, or a different 
expression should be used, e.g. “compared to”.  
 
 
 
 
Methods:  
 
-No concerns other than those mentioned above that relate to methods.  
Results:  
 
-No concerns other than those  mentioned above that relate to methods.  
 
 
 
 
Discussion:  
 
-There seems to be partial inadvertent duplication” This study addresses two important issues 
relevant to bowel preparation: a) the quality of preparation & b) the reduced PEG dosage needed 
for adequate  preparation.  
 
This study addresses three important issues relevant to bowel preparation: a) the quality of 
preparation b) the reduced PEG dosage needed for adequate preparation & c) effective same day 
preparation”.  
 
 
-How does the cost of lubiprostone compar e to bisacodyl?  The former is likely at least an order 
of magnitude more expensive and may be more difficult to gain access to, at least in the USA.  
This should be discussed.  
 
 
-The discussion is poorly organized.  For example, there are at least 16 separa te paragraphs; this 
should be more streamlined and better flowing.  
 
 
Tables and Figures are not seen in the PDF file.  
 
 
 
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
No 
 
Does the work i nclude the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
Yes 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
Yes 
Are you able to assess any statistics in the manuscript or would you recommend an  
additional statistical review?  
If an additional statistical review is recommended, please specify what aspects require further  
assessment in your comments to the editors.  
 
I am able to assess the statistics  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Not suitable for publication unless extensively edited  
 
 
 
 
Declaration of competing interests  
Please complete a declaration of competing inter ests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an  
organisation that may in any way gain or lose financially from the publication of this  
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose  
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the  
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds  or has applied for patents relating to the content of the manuscript?  
 
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare that I have no competing interests' 
below.  If you r reply is yes to any, please give details below.  
 
I declare that I have no competing interests  
  
I agree to the open peer review policy of the journal. I understand that my name will be included  
on my report to the authors and, if the manuscript is accepte d for publication, my named report  
including any attachments I upload will be posted on the website along with the authors'  
responses. I agree for my report to be made available under a n Open Access Creative Commons  
CC-BY license ( http://creativecommons.or g/licenses/by/4.0/ ). I understand that any comments  
which I do not wish to be included in my named report can be included as confidential comments  
to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal  
assistant