Review for 10.1186/1471-230X-11-86 (2011)

Reviewer's report
Title:Appointment waiting times and education level influence the quality of
bowel preparation in adult patients undergoing colonoscopy
Version: 1Date:28 April 2011
Reviewer: Ole Høie
Reviewer's report:
This article addresses the factors of influence, and the importance of a well
prepared bowel before colonoscopic examination in patients from the region of
Kuala Lumpur. The aim of the study is clearly expressed. The discussion and
conclusions are well balanced and in accordances with the results presented.
However some methodological and statistical issues need to be assessed. My
comments are listed below.
1 (major) The method of assessment of bowel preparation is described in four
categories. (pg. 7 line This method is based on two previously validated scales
(Ottawa scale and The Boston Bowel preparation scale). These two scales have
been reported with excellent inter-observer agreement. The scale used in this
study was evaluated in a pilot study with acceptable kappa-values only for
excellent and poor bowel cleaning. The two intermediate categories were then
collapsed creating a 3-category scale, and at the time of analysis regrouped into
a two-category scale. The reorganization of scales seems a bit confusing to me.
After the pilot study was performed, it had been better to chose a two category
scale as outcome measure before carrying out the main study. Alternatively on
could have used one of the scales which were already evaluated.
2 (major) Statistics. When assessing bowel preparation in the multiple logistic
regression analysis the authors report a significant (just at the limit, CI 1.01-2.47)
adjusted OR for gender (P=0.04). However the results for gender is far from
significant in the unadjusted analysis (p=0.35) It is unusual to include parameters
with unadjusted p values above 0.10 in adjusted regression models. Please
comment.
3 (major) The level of comfort and pain during the examination was made under
the influence of iv sedation. This is a limitation as pointed out by the authors. It is
not clear if the sedation was it given only before the start of the examination, or
additionally on demand during the procedure? If Pethidine was given additionally
during pain, this could influence the result of the analyses. Were there any
differences in the use of sedation between patients with poor and non-poor bowel
preparations?
4 (minor)Much of the data written in the results of risk factors (pg. 8) can also be
found in table 2. Please simplify. The information concerning senior endoscopists
and bowel preparation (pg. 9 line 13 to 16) is of limited interest and should be
removed from the manuscript. It could simply be added (line 17) Poor bowel
preparation was significantly associated with decreased cecal intubation rate,
prolonged cecal intubation time…..aso.
5 (minor) Waiting-time, does it mean the time from the patient receiving the
appointment till the examination is performed? (pg. 5 line 4)
6 (minor) Cecal intubation time and total colonoscopy time, how were they
assessed? Was it recorded by an endoscopy nurse using a stop-watch? Were
adjustments made for time performing therapeutic procedures? (pg. 5 line 8)
7(discretionally) The headline does not include the importance of a well prepared
colon which is a subject of the article. There is no paragraph on Aims in the
abstract. May be the headline Method could be changed to Aims and Methods?
Level of interest: An article of limited interest
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.