Review for 10.1186/s12876-015-0273-7 (2015)

Reviewer's report
Title:Difficult colonoscopy score identifies the difficult patients undergoing
unsedated colonoscopy
Version:4Date:29 December 2014
Reviewer: Aron Vincze Vincze
Reviewer's report:
Jia H et al, Difficult colonoscopy score identifies the difficult patients undergoing
unsedated colonoscopy
The prediction of difficult colonoscopy would have important clinical implication to
select the appropiate sedation level for the given patient, to schedule difficult
patients for properly experienced endoscopist, to select the adequat endoscope
for the patient, etc. We have limited knowledge about these factors, and would
need an easily applied, validated scoring system in the everyday practice. The
study of Jia H et al. is suggesting a new scoring system for the preprocedural
estimation of the difficulty of colonoscopy. It is correctly stated in the summary,
that the difficult colonoscopy scoring system should be validated in other
institutes and wider patient population.
Major Compulsory Revisions
1) Others also published similar scoring system recently, which should be
discussed and aknowledged in the paper (e.g., St. Mark’s scoring system,
Nakamura M et al, Gut 2012;61:A278).
2) Diverticular disease, laxative use, constipation, waist/hip ratio, previous
abdominopelvic surgery were also find to predict difficult colonoscopy in previous
studies (Anderson 2001, Nakamura M et al, Gut 2012;61:A278), however it is not
stated, why these factors were not analysed in the current study.
3) Methods, 5th paragraph: it is not clear how the bowel preparation was
evaluated, this should be clarified, Fig 2 is mentioning the Ottawa bowel
preparation scale
4) Table 4: More detailed data would be useful by separating patient goups with
DCS 0, 1, 2, 3 etc, and also the rate of difficult colonoscopy in each subgroup
can be included here for better overview of the results
5) Figure 2: the event definition is not clear, the figure legend refers to cecal
intubation within 10 minutes but from the numbers it looks like the opposite is the
case, more detailed figure legend should be given
Minor Essential Revisions
1) Abstract, 1st paragraph: „there is not a scoring system” – not proper English
wording
2) Background, 1st paragraph: Newer reference would be more appropriate to
use, e.g., ASGE/ACG Task Force on Quality in Endoscopy is recently updated
and published in the Am J Gastroenterol in December 2014, advising more than
95% cecal intubation rate target in screening procedures.
3) Methods, 1st paragraph: pregnancy instead of pregnant
4) Methods, 3rd paragraph: PEG powder instead of power; polyp detection rate
instead of polyps detection ...
5) Methods, 4th paragraph: Fujinon
6) Discussion, 4th paragraph: „anxious level”, and 5th paragraph „the difficulty
patients” are not proper terms
Discretionary Revisions
1) Bakground, 3rd paragraph: instead of „high-risk factors” use just risk factors
for difficult colonoscopy, same applies to 4th paragraph
2) Discussion, 1st paragraph: „early in these goups of patient to avoid of
excessive insertion time” seems to be more appropriate
Level of interest: An article of importance in its field
Quality of written English: Needs some language corrections before being
published
Statistical review: Yes, but I do not feel adequately qualified to assess the
statistics.
Declaration of competing interests:
I declare that I have no competing interests