Title: Anticoagulant Drugs With or Without Proton Pump Inhibitor and Colorectal Cancer Risk:
A Population-Based, Case-Control Study
Version: 3 Date: 21 Feb 2022
Reviewer's report:
There is a large bias in this study.
1) The ratio of the number of cases in CRC group and Non-CRC group is 1: 4. This is really
different from the general distribution.
2) More than 31% of the BMI, which is representative basic data, are missing.
3) The percentage of cases with Upper GI bleeding was 11.3% in the CRC group and 2.8% in
the Non-CRC group. This is a big bias. Taking PPI or anticoagulant was not thought to be the
cause of CRC. It is speculated that patients taking an anticoagulant may cause bleeding and in
such case CRC may have been discovered as a result of performed endoscopy and CT.
4) There seems to be a lot of overlap in the Comorbidity.
5) Table 2. The result was that the occurrence of CRC was low in the Low-dose aspirin +
Clopidogrel group, though the number of cases was too small.
From the above, it seems that the case selection in this study is incorrect. For example, it would
be better to correct the study design that matches the backgrounds of all CRC groups and Non-
CRC groups and compare the rate of administration of each drug.
Title: Anticoagulant Drugs With or Without Proton Pump Inhibitor and Colorectal Cancer Risk:
A Population-Based, Case-Control Study
Version: 3 Date: 21 Feb 2022
Reviewer's report:
There is a large bias in this study.
1) The ratio of the number of cases in CRC group and Non-CRC group is 1: 4. This is really
different from the general distribution.
2) More than 31% of the BMI, which is representative basic data, are missing.
3) The percentage of cases with Upper GI bleeding was 11.3% in the CRC group and 2.8% in
the Non-CRC group. This is a big bias. Taking PPI or anticoagulant was not thought to be the
cause of CRC. It is speculated that patients taking an anticoagulant may cause bleeding and in
such case CRC may have been discovered as a result of performed endoscopy and CT.
4) There seems to be a lot of overlap in the Comorbidity.
5) Table 2. The result was that the occurrence of CRC was low in the Low-dose aspirin +
Clopidogrel group, though the number of cases was too small.
From the above, it seems that the case selection in this study is incorrect. For example, it would
be better to correct the study design that matches the backgrounds of all CRC groups and Non-
CRC groups and compare the rate of administration of each drug.
Please review this paper.
user
Title: Anticoagulant Drugs With or Without Proton Pump Inhibitor and Colorectal Cancer Risk:
A Population-Based, Case-Control Study
Version: 3 Date: 21 Feb 2022
Reviewer's report:
There is a large bias in this study.
1) The ratio of the number of cases in CRC group and Non-CRC group is 1: 4. This is really
different from the general distribution.
2) More than 31% of the BMI, which is representative basic data, are missing.
3) The percentage of cases with Upper GI bleeding was 11.3% in the CRC group and 2.8% in
the Non-CRC group. This is a big bias. Taking PPI or anticoagulant was not thought to be the
cause of CRC. It is speculated that patients taking an anticoagulant may cause bleeding and in
such case CRC may have been discovered as a result of performed endoscopy and CT.
4) There seems to be a lot of overlap in the Comorbidity.
5) Table 2. The result was that the occurrence of CRC was low in the Low-dose aspirin +
Clopidogrel group, though the number of cases was too small.
From the above, it seems that the case selection in this study is incorrect. For example, it would
be better to correct the study design that matches the backgrounds of all CRC groups and Non-
CRC groups and compare the rate of administration of each drug.
assistant