Reviewer's report
Title:Unsedated Peroral Wireless pH Capsule Placement vs. Standard pH
Testing: A Randomized Study and Cost Analysis
Version: 2Date:3 March 2012
Reviewer: Stefan Öberg
Reviewer's report:
Major compulsory revisions
1. Discussion, first paragraph. The authors conclude that their study “confirms
that WC insertion is better tolerated than SC both overall and during placement”.
However, the study design does not allow the authors to make this conclusion as
this would require that all subjects underwent both tests in a cross-over study
design. The conclusion needs to be changed.
2. Statistics: Data obtained from VAS scales are usually not normally distributed.
The authors chose to assess differences in discomfort levels using means and
the Student t-test. If the data was normally distributed this needs to be stated and
if not, non-parametric statistical analysis should be used.
3. Most, if not all patients who undergo esophageal pH monitoring also undergo
an upper GI endoscopy. How many patients in the ESM+SC and ESM+WC
groups had an endoscopy shortly before or after the pH-study. As it is the total
cost for investigating symptoms suggestive of GERD that is of interest, the cost
of this additional endoscopy needs to be included in the analysis.
4. The analysis of the costs of the different strategies is based on more or less
well-documented assumptions that are regarded as facts in the statistical
analysis. This is a limitation of the study that needs to be mentioned in the
discussion.
5. Studies on adverse symptoms of pH monitoring has previously been
performed by other groups. The observations of these studies should be
mentioned and compared with the result of the present study.
6. Discussion, second paragraph. The two last sentences needs to be deleted as
efforts to validate the accuracy of the conversion factor was not made in the
present study.
Minor Essential Revisions
1. In the first paragraph of the Introduction it is stated that ambulatory
esophageal pH monitoring is the gold standard for establishing the diagnosis of
GERD. However, the diagnostic accuracy of esophageal pH monitoring is
relatively low and therefore no gold standard.
Level of interest: An article of importance in its field
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I declare that I have no competing interests.
Reviewer's report
Title:Unsedated Peroral Wireless pH Capsule Placement vs. Standard pH
Testing: A Randomized Study and Cost Analysis
Version: 2Date:3 March 2012
Reviewer: Stefan Öberg
Reviewer's report:
Major compulsory revisions
1. Discussion, first paragraph. The authors conclude that their study “confirms
that WC insertion is better tolerated than SC both overall and during placement”.
However, the study design does not allow the authors to make this conclusion as
this would require that all subjects underwent both tests in a cross-over study
design. The conclusion needs to be changed.
2. Statistics: Data obtained from VAS scales are usually not normally distributed.
The authors chose to assess differences in discomfort levels using means and
the Student t-test. If the data was normally distributed this needs to be stated and
if not, non-parametric statistical analysis should be used.
3. Most, if not all patients who undergo esophageal pH monitoring also undergo
an upper GI endoscopy. How many patients in the ESM+SC and ESM+WC
groups had an endoscopy shortly before or after the pH-study. As it is the total
cost for investigating symptoms suggestive of GERD that is of interest, the cost
of this additional endoscopy needs to be included in the analysis.
4. The analysis of the costs of the different strategies is based on more or less
well-documented assumptions that are regarded as facts in the statistical
analysis. This is a limitation of the study that needs to be mentioned in the
discussion.
5. Studies on adverse symptoms of pH monitoring has previously been
performed by other groups. The observations of these studies should be
mentioned and compared with the result of the present study.
6. Discussion, second paragraph. The two last sentences needs to be deleted as
efforts to validate the accuracy of the conversion factor was not made in the
present study.
Minor Essential Revisions
1. In the first paragraph of the Introduction it is stated that ambulatory
esophageal pH monitoring is the gold standard for establishing the diagnosis of
GERD. However, the diagnostic accuracy of esophageal pH monitoring is
relatively low and therefore no gold standard.
Level of interest: An article of importance in its field
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I declare that I have no competing interests.
Please review this paper.
user
Reviewer's report
Title:Unsedated Peroral Wireless pH Capsule Placement vs. Standard pH
Testing: A Randomized Study and Cost Analysis
Version: 2Date:3 March 2012
Reviewer: Stefan Öberg
Reviewer's report:
Major compulsory revisions
1. Discussion, first paragraph. The authors conclude that their study “confirms
that WC insertion is better tolerated than SC both overall and during placement”.
However, the study design does not allow the authors to make this conclusion as
this would require that all subjects underwent both tests in a cross-over study
design. The conclusion needs to be changed.
2. Statistics: Data obtained from VAS scales are usually not normally distributed.
The authors chose to assess differences in discomfort levels using means and
the Student t-test. If the data was normally distributed this needs to be stated and
if not, non-parametric statistical analysis should be used.
3. Most, if not all patients who undergo esophageal pH monitoring also undergo
an upper GI endoscopy. How many patients in the ESM+SC and ESM+WC
groups had an endoscopy shortly before or after the pH-study. As it is the total
cost for investigating symptoms suggestive of GERD that is of interest, the cost
of this additional endoscopy needs to be included in the analysis.
4. The analysis of the costs of the different strategies is based on more or less
well-documented assumptions that are regarded as facts in the statistical
analysis. This is a limitation of the study that needs to be mentioned in the
discussion.
5. Studies on adverse symptoms of pH monitoring has previously been
performed by other groups. The observations of these studies should be
mentioned and compared with the result of the present study.
6. Discussion, second paragraph. The two last sentences needs to be deleted as
efforts to validate the accuracy of the conversion factor was not made in the
present study.
Minor Essential Revisions
1. In the first paragraph of the Introduction it is stated that ambulatory
esophageal pH monitoring is the gold standard for establishing the diagnosis of
GERD. However, the diagnostic accuracy of esophageal pH monitoring is
relatively low and therefore no gold standard.
Level of interest: An article of importance in its field
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I declare that I have no competing interests.
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