Review for 10.1186/s12876-022-02439-y (2022)

Reviewer’s report
Title: 
Subcutaneous administration, higher age and lower renal function are associated with erythrocyte
methotrexate accumulation in Crohn’s disease: a cross-sectional study
Version: 
0 
Date: 
05 May 2022
Reviewer: 
Masaru Shinozaki
Reviewer's report:
Adherence to methotrexate (MTX) therapy should be assessed for accurate analyses.
I think BMC Gastroenterology is a clinical journal. In this study, the authors included only patients who
had been on MTX with median duration of 77 months. In these patients, MTX seem to have been effective
and without major adverse effects, that is, on appropriate dose. Please explain clearly what is clinically
important regarding the concentration of MTX in this population.
The number of patients investigated was very small.
I think that an additional analysis regarding erythrocyte turnover is needed. As well known, massive or
continuous bleeding may sometimes occur in patients with Crohn's disease.
If the authors investigated not only erythrocytes but also cell from other tissue, the title is OK, otherwise
the title should be changed.
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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
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Yes
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Yes
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