Review for 10.1186/s12876-023-03008-7 (2023)

Title: Clinical importance of weight gain and associated factors in patients with moderate to
severe ulcerative colitis: Results from the MOSAIK cohort in Korea
Version: 1 Date: 03 Jun 2023
Reviewer's report:
Abstract-please indicate the number of patients and the period of follow up in the Methods.
Background
The authors do not seem to effectively convey why there is a need for a study on the clinical
significance of a significant weight gain among patients with ulcerative colitis, which is basically
what they are trying to do.
“Furthermore” in the second paragraph is a bit awkward choice of word # What points do the
authors try to augment?
In fact, the authors overdid the use of conjunctive words in the second paragraph, which do not
necessary help the flow of sentences. Please consider rewriting.
Please clearly state that this study will examine the clinical significance of a significant weight
gain in terms of relapse, hospitalization, adverse outcomes, or whatever, even if it is later detailed
in the methods.
Methods
“This study was conducted in accordance with the Declaration of Helsinki and approved by the
institutional review boards of all participating hospitals. Written informed consent was obtained
from all the participants. This study was registered at www.clinicaltrials.gov (ClinicalTrials.gov
identifier: NCT02229344).” There must be a subheading for this under Methods. Or move the
paragraph to another location.
Patients
Give more information on the dataset used, such as the number of patients and the years when
the patients were enrolled in the cohort.
“who recruited patients from” # “who were recruited from”
Definitions
Asia-Pacific criteria of the World Health Organization guidelines # need to cite a reference.
Statistical analysis should comprehensively and thoroughly describe all of the analyses the
authors conducted. However, the section omitted lots of information, for example, median,
covariates other than age and sex, HR, reference categories.
Results
Aren’t the supplementary tables the highlights of this study, which present “clinical
significance”? I presume they should take the center stage as the main tables.
The first paragraph of the results should better be located in the Methods section.
In Table 3, why are there missing results for some variables like weight loss at diagnosis,
smoking history, and the like? Please explain in the text and as a note to the table. If the authors
intentionally leave the variables out, please explain in the methods-statistical analyses section.
Also indicate what the reference groups were in the Table.
Please consider treating age as a categorical variable instead of a continuous variable for improve
interpretability.
Discussion
“in studies conducted on the entire Korean population” # need to cite references.
“(HR, 2.8; 95% CI, 1.1–7.0, p = 0.026) (Supplementary Table S3)” # please avoid presenting
statistics in the discussion section. Instead focus on discussing the implications of the findings.
Conclusion is weak. Please highlight the clinical importance of the findings in terms of relapse,
adverse outcomes, etc.? Also what are recommendations in terms of future research and clinical
decision making?