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: 17 Jul 2023
Reviewer:  Andreas Stallmach
Reviewer's report:
In the paper titled "The long-term effect on surgery-free survival of biological compared to
conventional therapy in Crohn's disease in real-world data: a propensity-score matched study"
submitted by Valvano et al., the authors conducted a retrospective study comparing surgery-
free survival since the diagnosis of Crohn's disease (CD) between biological and conventional
therapies. They demonstrated that the introduction of biologicals appears to delay surgery but
has only a slight impact on the occurrence of surgery. The study was carefully conducted, and
the results are important for readers of BMC Gastroenterology. Minor suggestions can improve
the manuscript t
Minor point of criticism:
1. Abstract, background: Please delete the second statement in the first paragraph.
2. Statistical analysis: The authors mentioned that unmatched observations were excluded from
the analysis. However, it is unclear to me how many patients were included in the PSC matching
analysis. Please include this information in the abstract section.
3. Table 1 mentions 159 patients in the conventional arm, while Table 2 mentions 154 patients (I
think 154 is the correct number). Please indicate the number of ex-smokers (quitters) in Table 1.
4. Figure 3, 4 and 5 can be deleted.
5. Discussion: Please start the "Discussion" section with an introductory sentence.
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: 17 Jul 2023
Reviewer:  Andreas Stallmach
Reviewer's report:
In the paper titled "The long-term effect on surgery-free survival of biological compared to
conventional therapy in Crohn's disease in real-world data: a propensity-score matched study"
submitted by Valvano et al., the authors conducted a retrospective study comparing surgery-
free survival since the diagnosis of Crohn's disease (CD) between biological and conventional
therapies. They demonstrated that the introduction of biologicals appears to delay surgery but
has only a slight impact on the occurrence of surgery. The study was carefully conducted, and
the results are important for readers of BMC Gastroenterology. Minor suggestions can improve
the manuscript t
Minor point of criticism:
1. Abstract, background: Please delete the second statement in the first paragraph.
2. Statistical analysis: The authors mentioned that unmatched observations were excluded from
the analysis. However, it is unclear to me how many patients were included in the PSC matching
analysis. Please include this information in the abstract section.
3. Table 1 mentions 159 patients in the conventional arm, while Table 2 mentions 154 patients (I
think 154 is the correct number). Please indicate the number of ex-smokers (quitters) in Table 1.
4. Figure 3, 4 and 5 can be deleted.
5. Discussion: Please start the "Discussion" section with an introductory sentence.
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: 17 Jul 2023
Reviewer:  Andreas Stallmach
Reviewer's report:
In the paper titled "The long-term effect on surgery-free survival of biological compared to
conventional therapy in Crohn's disease in real-world data: a propensity-score matched study"
submitted by Valvano et al., the authors conducted a retrospective study comparing surgery-
free survival since the diagnosis of Crohn's disease (CD) between biological and conventional
therapies. They demonstrated that the introduction of biologicals appears to delay surgery but
has only a slight impact on the occurrence of surgery. The study was carefully conducted, and
the results are important for readers of BMC Gastroenterology. Minor suggestions can improve
the manuscript t
Minor point of criticism:
1. Abstract, background: Please delete the second statement in the first paragraph.
2. Statistical analysis: The authors mentioned that unmatched observations were excluded from
the analysis. However, it is unclear to me how many patients were included in the PSC matching
analysis. Please include this information in the abstract section.
3. Table 1 mentions 159 patients in the conventional arm, while Table 2 mentions 154 patients (I
think 154 is the correct number). Please indicate the number of ex-smokers (quitters) in Table 1.
4. Figure 3, 4 and 5 can be deleted.
5. Discussion: Please start the "Discussion" section with an introductory sentence.
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