Review for 10.1186/s12876-022-02157-5 (2022)

Reviewer’s report
Title: 
Systematic Review and Meta-Analysis: the advantage of Endoscopic
Mayo Score 0 over 1 in patients with Ulcerative Colitis.
Version: 
1 
Date: 
15 Nov 2021
Reviewer: 
Gian Eugenio Tontini
Reviewer's report:
Dear Authors,
I have carefully read the manuscript by Dr. Angelo Viscido et al. entitled
"Systematic Review and Meta-Analysis: the advantage of Endoscopic Mayo
Score 0 over 1 in patients with Ulcerative Colitis."
This systematic review with meta-analysis evaluates the added value of deep
mucosal healing (Mayo endoscopic subscore, MES, 0) over partial mucosal
healing (MES 1) assess by colonoscopy in patients with ulcerative colitis
followed for no less than 12 months.
In contrast to previous systematic review in this field, here, for the first time
ever, other definition of MH (other index) and patient without established
clinical steroid free remission were not included to avoid potential bias.
After a rigours selection and methodological assessment (PROSPERO 2020),
fifteen studies (with 1617 patients) with a focus on clinical relapse and data on
MES 0
(901 pts) or MES 1 (716) were included.
Patients in MES 0 have a lower risk of clinical relapse (OR 0.33; 95% CI, 0.26-
0.43; I2 13%) irrespective of the follow-up length (12-months or longer).
No differences were found comparing MES 0 versus MES 1 about the risk of
hospitalization or colectomy.
The manuscript is fluent. Table and figures are clear and comprehensive.
The topic is of interest since MH is the best goal of modern treatment strategies
for UC.
The conclusion is not completely new as two previous systematic reviews (cited
and discussed by the Authors in the discussion section, 48,49) have already
highlighted the importance of complete over partial endoscopic healing.
However, this confirmatory evidence has been obtained using a more selected
search strategy to reduce the risk of bias.
Consistently, the manuscript as the potential to rise the readers' attention and the
interest of the scientific community involved in this growing research field 
I found only few major and minor comment.
Major comment
1) Several studies have shown that even MES 0 is imperfect for providing a
reliable definition of deep mucosal healing (suboptimal sensiticity and
interobserver agreement) as histological inflammatory activity is frequently
present. However, in a recent large study using HD, training and expert
endoscopic raters, both MES 0, UCEIS ≤1 and PICASSO ≤3 were able to
properly predict histologic remission (Iacucci M. Gastroenterology. 2021
Apr;160(5):1558-1569.e8.). 
Please mention the use of HD or standard definition imaging in your selected
studies.
Please consider a subanalysis evaluating the risk of clinical relapse with and
without HD-defined MES 0: MES 0 (anyway or better if HD driven?) should be
considered the optimal therapeutic goal as it predicts the best clinical course in
patients with UC.
Minor comments
2) Methods
Please consider moving some section of this chapter in a supplementary file (e.g.
Data extraction and assessment of studies quality) to further improve the
manuscript fluency.
3) I suggest language revision by native speaker (for minor language revisions)
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Declaration of competing interests
Please complete a declaration of competing
interests, considering the following questions:
1
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Have you in the past five years received reimbursements, fees, funding, or
salary from an organisation that may in any way gain or lose financially
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Do you hold any stocks or shares in an organisation that may in any way
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Do you hold or are you currently applying for any patents relating to the
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Have you received reimbursements, fees, funding, or salary from an
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Do you have any non-financial competing interests in relation to this
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If you can answer no to all of the above, write 'I declare that I have no competing
interests' below. If your reply is yes to any, please give details below.
I declare that I have no financial competing interests.I have co-worked with
Giovanni Latella in previous research experiences as we are member of the
European Microscopic Colitis Group
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Is the study design appropriate to answer the research question (including the use
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presented?
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from apparent manipulation?
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