Title: The long-term effect on surgery-free survival of biological compared to conventional
therapy in Crohn’s disease in real world-data: a retrospective study.
Version: 2 Date: 04 Sep 2023
Reviewer's report:
There are quite a few problems with this study that make the conclusions unreliable.
1.The primary outcome was the surgery-free survival defined as the time from the diagnosis
to the first bowel resection. Therefore factors affecting the diagnosis also posed effects to the
surgery-free survival, since improved diagnostic methods over time (before vs. after 1998) had
led to an earlier age of diagnosis. The age at diagnosis among enrolled patients should be given.
Secondly, is there possibility to analyze the time from symptom to the first bowel resection?
2. The previous medication history of the biological patients deserved attention. Had they
received conventional therapy before? if so, this step-up treatment strategy signified more severe
disease in the biological group, which reduced the reliability of the conclusions. The disease
duration was longer in the biological compared to the conventional group, also consolidating
the above opinion.
3. Table 3 should be presented  in a better fashion. More specific descriptions should be given
for Figure 1 and 2.
4. Do not repeat the results (such as P value) in the Discussion section.
Title: The long-term effect on surgery-free survival of biological compared to conventional
therapy in Crohn’s disease in real world-data: a retrospective study.
Version: 2 Date: 04 Sep 2023
Reviewer's report:
There are quite a few problems with this study that make the conclusions unreliable.
1.The primary outcome was the surgery-free survival defined as the time from the diagnosis
to the first bowel resection. Therefore factors affecting the diagnosis also posed effects to the
surgery-free survival, since improved diagnostic methods over time (before vs. after 1998) had
led to an earlier age of diagnosis. The age at diagnosis among enrolled patients should be given.
Secondly, is there possibility to analyze the time from symptom to the first bowel resection?
2. The previous medication history of the biological patients deserved attention. Had they
received conventional therapy before? if so, this step-up treatment strategy signified more severe
disease in the biological group, which reduced the reliability of the conclusions. The disease
duration was longer in the biological compared to the conventional group, also consolidating
the above opinion.
3. Table 3 should be presented  in a better fashion. More specific descriptions should be given
for Figure 1 and 2.
4. Do not repeat the results (such as P value) in the Discussion section.
Please review this paper.
user
Title: The long-term effect on surgery-free survival of biological compared to conventional
therapy in Crohn’s disease in real world-data: a retrospective study.
Version: 2 Date: 04 Sep 2023
Reviewer's report:
There are quite a few problems with this study that make the conclusions unreliable.
1.The primary outcome was the surgery-free survival defined as the time from the diagnosis
to the first bowel resection. Therefore factors affecting the diagnosis also posed effects to the
surgery-free survival, since improved diagnostic methods over time (before vs. after 1998) had
led to an earlier age of diagnosis. The age at diagnosis among enrolled patients should be given.
Secondly, is there possibility to analyze the time from symptom to the first bowel resection?
2. The previous medication history of the biological patients deserved attention. Had they
received conventional therapy before? if so, this step-up treatment strategy signified more severe
disease in the biological group, which reduced the reliability of the conclusions. The disease
duration was longer in the biological compared to the conventional group, also consolidating
the above opinion.
3. Table 3 should be presented  in a better fashion. More specific descriptions should be given
for Figure 1 and 2.
4. Do not repeat the results (such as P value) in the Discussion section.
assistant