Review for 10.1186/s12876-021-01817-2 (2021)

Title: A Multicenter, Prospective, Inpatient Feasibility Study to Evaluate the Use of an Intra-
Colonoscopy Cleansing Device to Optimize Colon Preparation in Hospitalized Patients - The
REDUCE Study
Version: 2 Date: 21 Feb 2021
Reviewer:  Yu-Hsi Hsieh
Reviewer's report:
Summary based on the authors’ abstract
The authors aimed to evaluate optimization of bowel preparation quality by using the Pure-Vu
System during colonoscopy in inpatients in a multicenter, prospective study.  Subjects recorded
the clarity of their last bowel movement using a 5-point scale prior to colonoscopy.  The primary
endpoint was improvement of colon cleanliness from baseline to post-procedure as assessed
by the improvement in Boston Bowel Preparation Scale (BBPS) following cleansing with the
Pure-Vu System.  The results included 94 subjects. BBPS showed significant improvements
across all colon segments, including left colon (1.74 vs 2.89; p<0.0001), transverse colon (1.74
vs 2.91; p<0.0001), and the right colon (1.41 vs 2.88; p<0.0001). Compared with those before
the cleansing with the Pure-Vu System, adequate cleansing (BBPS scores of #2) increased from
60%, 62%, and 47% to 100%, 99%, and 97% for the left colon, transverse colon, and right colon
segments, respectively. Subjects with lower bowel movement clarity scores were more likely
to have inadequate bowel preparation prior to cleansing with Pure-Vu. The authors concluded
that the Pure-Vu System appears to be effective in significantly improving bowel preparation
quality in hospitalized subjects undergoing colonoscopy. Clarity of last bowel movement may
be useful indicator in predicting poor bowel preparation.
Strengths
1. A multicenter study
2. Evaluation of a novel intra-colonoscopy cleansing device in hospitalized patients
Weakness
1. Not a randomized, control trial.
2. Small sample size.
Major comments
1. The title “A Multicenter, Prospective, Inpatient Feasibility Study to Evaluate the Ability of a
Stool Clarity Score to Predict Bowel Preparation Quality and the Use of an Intra-Colonoscopy
Cleansing Device to Optimize Colon Preparation in Hospitalized Patients - The REDUCE
Study”. Please consider delete “the Ability of a Stool Clarity Score to Predict Bowel Preparation
Quality and” so that the readers can catch the key point of the study on a glance.
2. The authors stated “Pre-colonoscopy bowel preparation typically included diet restrictions
and 4 liters of GoLYTELY® [Braintree Laboratories, Inc., Braintree, MA, USA] within the 24
hours prior to their colonoscopy.” Was the bowel prep split dose? How many patients completed
the bowel prep?
3. The authors stated” The BBPS score was recorded for each colorectal segment (left colon,
transverse colon, and right colon segments) both prior to (baseline) and after colon cleansing
with Pure-Vu.” How did the authors acquire the baseline BBPS score? Did they intubate the
subject twice, once for baseline score and the second for post-cleansing score? Or did they reach
one segment and acquire the scores before and after cleansing? Please clarify.
4. Table 2. All included subjects were supposed to have the BBPS scores in all 3 colonic
segments. Why the number of N was different in the segments?
5. The results showed “Colonoscopy was performed with an adult size colonoscope with Pure-
Vu System Oversleeve in 53 subjects (56.4%) and with a pediatric/slim size colonoscope with
Pure-Vu System Oversleeve in 41 subjects.” Why the endoscopists chose to use pediatric scopes
in almost half of the patients? Was that related to the use of Oversleeve?
6. There were one major (perforation) and 3 minor adverse effects out of 94 patients. This might
deter other endoscopists from adopting the Pure-Vu system. Please discuss these adverse effects.
7. The patient flow in Figure 3 is confusing. Why did 10 included patients intubated without
the Pure-Vu system? Were these patients the same as the “10 subjects the cecum was reached
after switching to a naked pediatric / slim colonoscope.” as the authors stated in the results?
Please clarify and modify. In addition to 2 patients with incomplete colonoscopy due to looping,
there were 11 patients with diagnosis prior to cecal intubation, that is, without cecal intubation.
Therefore, the successful intubation with Pure Vu system was far less than the 98% reported
in Figure 3.
8. In the results the authors state” We observed that 70% of subjects with a self-reported lower
clarity score of 1, 2, or 3 (poor clarity of last bowel movement) had at least one inadequately
prepared colonic segment (BBPS <2).” And in the abstract the authors suggested “Subjects with
lower bowel movement clarity scores were more likely to have inadequate bowel preparation
prior to cleansing with Pure-Vu.” Please provide a statistic analysis and P value to support your
findings.
Minor comments
1. Study population, please delete “abdominal” from “abdominal ascites”.
2. Discussion, 3rd paragraph, the statement “Similar to a recently published prospective, single-
blind, randomized trial, the volume of purgative consumed did not correlate to the level of
preparation in the inpatient setting.14” is misleading. The cited article reported that 75% or
more intake of bowel preparation (OR, 0.09; 95% CI, 0.05-0.15) significantly reduced odds of
inadequate colon cleansing.
3. Table 1, “**abnormal image” is not compatible with the description of ** in the footnote.