Review for 10.1186/s12876-023-02823-2 (2023)

Reviewer’s report
Title: 
Lower ultra-short-term heart rate variability can predict worse mucosal
healing in ulcerative colitis
Version: 
1 
Date: 
12 Jan 2023
Reviewer's report:
This is an interesting study on the relationship between ultra-short-term heart rate
variability (HRV) and mucosal inflammation in ulcerative colitis.
The study objective is of scientific interest. The sample size is adequate.
But there are several points that need to be addressed.
1.According to the results of this study, "HRV is a risk factor" does not seem
appropriate.
The design of this study is a case control study. HRV was measured only once at
the time of admission, and changes over time were not observed. Therefore, the
results of this study show an association between HRV and mucosal findings,
but do not tell us which is the cause, and which is the result. HRV changes may
not be the cause of inflammation of UC but may be the result of an autonomic
nervous system's response to systemic inflammation. If so, it would make sense
that HRV responded to endoscopic inflammation with systemic inflammation,
but not to histological inflammation without systemic effects.
Based on the results of this study, it can be said that there is an association
between HRV and endoscopic findings, but HRV may not be a "risk factor" for
mucosal flare. Please re-consider your title and discussion.
2.It would be good if you could discuss the reasons why RMSSD
(parasympathetic nervous system) was extracted and SDNN and SDSD (both
sympathetic and parasympathetic) were not extracted, based on their respective
mechanisms.
3.In the discussion section, the contents of the introduction section are repeated.
This is redundant.
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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?
Yes
Are the methods sufficiently described to allow the study to be repeated?
Yes
Is the use of statistics and treatment of uncertainties appropriate?
Yes
Is the presentation of the work clear?
Yes
Are the images in this manuscript (including electrophoretic gels and blots) free
from apparent manipulation?
Yes
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No