Review for 10.1186/s12876-023-02696-5 (2023)

Reviewer’s report
Title: 
A novel capsule endoscopy for upper and mid-GI tract: the UMGI capsule
Version: 
0 
Date: 
17 Aug 2022
Reviewer's report:
In this pilot study, the Authors investigate the feasibility of a new "hybrid
capsule" for the examination of both upper and middle gastrointestinal tract. The
topic and the technology are very interesting and I am enthusiastic about future
development in the field on non- or minimally-invasive diagnostics in
Gastroenterology. 
However, I have some concerns about the study that need to be addressed before
publication. Overall I think the study design and the results are optimal for a
pilot/feasibility study for the upper GI part of the UMGI capsule examination,
while they are not convincing when it comes to the use as an hybrid, 
complete
upper+middle GI capsule. 
Major issues
1. This new capsule is supposed to visualise optimally both Upper and Middle
GI tract (and I presume the Authors mean: the whole small bowel). However,
just few words are spent on the performances of the capsule in the small bowel
(type of preparation, quality of preparation..). 
Moreover, it is stated that only in 22 patients the small bowel examination was
executed, but why? Supposedly it was a feasibility study, which was also
supposed to test battery duration and performance in the small bowel and the
capsule was detached anyway so why not report data from the small bowel part
of the examination in these 7 patients? 
Without these data should we infere a possible 22/30 complete examination rate
(including the capsule which did not detach which counts as a failure of
complete examination)? 
2. The Methods section is very synthetic but important details are missing: what
were the inclusion criteria for the patients? in the results it is reported that 12
where healty volunteers and the others had other GI complaints but more data on
the way the subjects were enrolled need to be reported in the Methods section. 
3. If the clinical indication for the performance of a whole upper and middle
tract examination was not clear or mixed (some volunteers, some functional GI
disorders etc) , then even the diagnostic yield and the comparison with
gastroscopy are not very meaningful, especially since the gastroscopy was
performed up to 1 week after the capsule examination (median and range are not
reported). At least a further endpoint "detection of clinically relevant lesions" for
patients with symptoms should be evaluated. 
Minor issues:
1. in the abstract, it should be cleally stated which was the main outcome and
which were the secondary outcomes of the study 
2. technical data like image collection ( wireless recorder, within the capsule),
battery duration, nr. images per seconds are missing, maybe they were already
reported in previous papers but in my opinion they are necessary in the Methods
section of a pilot/feasibility study
3. I find it quite confusing that some data are presented as mean and some as
median within the same set of data (transit time: ösophagus - median, gastric -
mean, pylorus - median, small bowel - mean), please uniform the reporting. 
4. If I understand correctly, the overall discomfort score is rated from 0 to 10 not
as plain NRS but as comparison with the discomfort caused by the gastroscopy,
but 
a) there are no details about how the upper GI endoscopy was performed: with or
no sedation? pain medication? propofol? midazolam? xylocaine spray? This
greatly influences the discomfort during endoscopy!
b) assuming that endoscopy was without sedation, patients underwent the
gastroscopy after the capsule examination and where then asked to compare the
memory of the discomfort caused by the capsule examination with the
gastroscopy. This timing of evaluation and relative use of NRS is prone to
biases, usually a standard absolute NRS score 0 to 
10 should be colelcted after
each examination and the scores should be statistically compared. 
5. an extensive language revision is required
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Is the study design appropriate to answer the research question (including the use
of appropriate controls), and are the conclusions supported by the evidence
presented?
No
Are the methods sufficiently described to allow the study to be repeated?
No
Is the use of statistics and treatment of uncertainties appropriate?
Yes
Is the presentation of the work clear?
No
Are the images in this manuscript (including electrophoretic gels and blots) free
from apparent manipulation?
Yes