Review for 10.1186/s12876-022-02505-5 (2022)

Title: Association between metabolic syndrome and colorectal cancer incidence and all-cause
mortality: a hospital-based observational study
Version: 3 Date: 26 May 2022
Reviewer's report:
Major comments:
1. The article needs language polishing, and many sentences are not clear to read. For example,
‘This study aims to identify the effect of the components of MetS in CRC using national,
longitudinal hospital care data.’
2. Methods section in Abstract is not presented properly with key description missing.
3. HR needs to be present as value with 95% CI and p value in the manuscript.
4. The current study was not a population-based study. I suggest to modify the title as
‘Association between metabolic syndrome and colorectal cancer incidence and all-cause
mortality: a hospital-based observational study’. An additional analysis on the association
between metabolic syndrome and colorectal cancer-related mortality is strongly recommended.
5. For Conclusions, Additive effect is a specific term that needs specific analysis, and the current
analyses cannot support the conclusion. Additionally, the conclusion should be summative,
rather than simply repeating the result.
6. The English abbreviation needs to be written in full when it first appears, eg, IRB.
7. For study population, 1) patients aged less than 40 years old should be excluded, if not, the
association of MetS and CRC incidence may be underestimated; 2) patients without MetS needs
to be added as control group; 3) exclusion criteria should be concretely present in Figure 1; 4) the
matching condition of propensity score matching should be described clearly; 5) the definition of
comorbidities needs to be clearer; 6) Is the follow-up time for the patients who were included in
2008-2009 is too short to meet the included criterion that one inpatient diagnosis or 2 outpatient
visits with any components of MetS found within one year.
8. Provide the reference for the diagnosis of MetS, and provide reference to support the
rationality of replacing the missing indicator with the current indicator. Eg, replace waist
circumference with obesity
9. The definition of disease should be described concretely in the manuscripts, eg, obesity,
hyperlipidemia, etc.
10. “Due to the limitation of the database, only four components of MetS were used in this
study.” is misunderstanding.
11. The section of Subgroup Analyses should be written in the section of Statistical Analysis
12. Please define when statistic tests is considered as significant in Statistical Analysis
13. Please explain why the current results is inconsistent with previous study in discussion. Eg,
“In this study, a significantly increased risk of CRC in men is associated with more components
of MetS, approximately 3.6-fold than in women. Therefore, it might shed new light on the
influence of numbers of MetS components on gender-related CRC risk.”
14. In all tables, please explain and mark if there are missing values in some subgroups, and
provide the reason, and the way to process.
15.  The characteristic with respect to Alcohol drinking and liver disease needs to present
separately in Table 1
16. There is no need to display the baseline characteristic for participants who are prior to PS
matching in Table 1
17. Please explain the meaning for p value in Table 3
18. The sentence, “Adjusted for all the covariates.”, in table 3 is not clear