Review for 10.1186/s12876-020-01454-1 (2020)

Reviewer’ s report
Title: The Effect of Prophylactic Hemoclip Placement and Risk Factors of Delayed Post-
polypectomy Bleeding in Polyps Sized 6 to 20 Millimeters: A Propensity Score MatchingAnalysis
Version: 0Date: 01 Jun 2020
Reviewer: Jun Arimoto
Reviewer's report:
This experimental study evaluated the association of prophylactic clipping and the rate of delayed
bleeding.This is well written study and novel information, however, this study has serious limitations in thefollowing areas.
1.I think that the procedure in this study is not polypectomy. Author described "Before snare
polypectomies, an adequate volume of normal saline solution was injected into the submucosabeneath the sessile polyps through an injection needle." I think this procedure is EndoscopicMucosal Resection (EMR). What is the difference between EMR and the procedure in this study?2.Clipping technique is important and the skill level of the endoscopists may influences the results.Please show the endoscopic images of the clipping cases on additional figures.3.Why did you exclude polyps smaller than 5 mm?4.How authors estimated the polyp size? Authors described "The size of polyps was measured bycomparing it with the size of the snare." However, the width of the sheath of the snare is about
3mm. I think it is difficult to judge 5mm and 6mm. Since authors excluded the polyps smaller than
5 mm, I think this is an important issue of this study. Please explain.5.Authors excluded the cases with immediate bleeding after resection requiring an endoscopichemostasis procedure. Why? I think it is desirable that authors show the data whether immediatebleeding and delayed bleeding are related.
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
NoDoes the work include the necessary controls?
If not, please specify which controls are required in your comments to the authors.
YesAre 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 furtherassessment in your comments to the editors.
Not relevant to this manuscript
Quality of written English
Please indicate the quality of language in the manuscript:
AcceptableDeclaration of competing interests
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