Title: A retrospective cohort study on oesophageal food bolus obstruction in the North Denmark
Region in 2021 - two thirds were never diagnosed with a cause
Version: 2 Date: 13 Sep 2023
Reviewer's report:
This study by Terkelsen et al aims at investigating causes and treatment of food bowel
obstruction (FBO), adherence to clinical guidelines, and usage of diagnostic codes to capture
hospital visits for FBO.  The authors conclude that the causes of FBO were rarely found and that
adherence to clinical guidelines recommending gastroscopy was low. Comments to consider:
1. Suggest that the authors consult STROBE guidelines to strengthen the structure of the
manuscript.
2. It is unclear from the introduction which gap in the existing evidence this study aims
at addressing. Why is this study relevant for an international audience? What may be new
knowledge here?
3. The study is limited by the fact that it is purely descriptive and only represents a few hospitals.
This fact underlines the need for the authors to provide a very strong reason why this study
belongs in an international journal.
4. The method section is unclear. Again, the authors should consult STROBE guidelines. For
instance, the design of the study is not mentioned, but is pivotal for the understanding. The
authors have conducted a cross-sectional (also called prevalence) study including both new and
prevalent FBO cases. It is very important to distinguish prevalent from incident FBO cases, but
the authors only do that to a limited extent. All analysis should be stratified by prevalent and
incident FBO cases.
5. The identification of patients by using ICD-10 and procedure codes is not completely
clear. Did the authors use registry data to identify patients? Did they use discharge or referral
codes? Did they only identify patients with acute admission or patients admitted at specific
departments? How many hospital are included? What is meant by “filtered using selected
ICD-10 codes…”? And what is meant by “…and codes for enteroscopy, colonoscopy and
sigmoidoscopy applied were excluded”? Does it mean that cases with relevant ICD-10 codes in
combination with these procedure codes were excluded?
6. The manuscript would be improved substantially by including validation of codes to capture
FBO. The authors mention a combination of codes that would capture the majority of FBO
cases, but do not mention if this combination of codes also capture irrelevant cases. Ideally, the
combination of codes would be tested in a different setting for validation.
Title: A retrospective cohort study on oesophageal food bolus obstruction in the North Denmark
Region in 2021 - two thirds were never diagnosed with a cause
Version: 2 Date: 13 Sep 2023
Reviewer's report:
This study by Terkelsen et al aims at investigating causes and treatment of food bowel
obstruction (FBO), adherence to clinical guidelines, and usage of diagnostic codes to capture
hospital visits for FBO.  The authors conclude that the causes of FBO were rarely found and that
adherence to clinical guidelines recommending gastroscopy was low. Comments to consider:
1. Suggest that the authors consult STROBE guidelines to strengthen the structure of the
manuscript.
2. It is unclear from the introduction which gap in the existing evidence this study aims
at addressing. Why is this study relevant for an international audience? What may be new
knowledge here?
3. The study is limited by the fact that it is purely descriptive and only represents a few hospitals.
This fact underlines the need for the authors to provide a very strong reason why this study
belongs in an international journal.
4. The method section is unclear. Again, the authors should consult STROBE guidelines. For
instance, the design of the study is not mentioned, but is pivotal for the understanding. The
authors have conducted a cross-sectional (also called prevalence) study including both new and
prevalent FBO cases. It is very important to distinguish prevalent from incident FBO cases, but
the authors only do that to a limited extent. All analysis should be stratified by prevalent and
incident FBO cases.
5. The identification of patients by using ICD-10 and procedure codes is not completely
clear. Did the authors use registry data to identify patients? Did they use discharge or referral
codes? Did they only identify patients with acute admission or patients admitted at specific
departments? How many hospital are included? What is meant by “filtered using selected
ICD-10 codes…”? And what is meant by “…and codes for enteroscopy, colonoscopy and
sigmoidoscopy applied were excluded”? Does it mean that cases with relevant ICD-10 codes in
combination with these procedure codes were excluded?
6. The manuscript would be improved substantially by including validation of codes to capture
FBO. The authors mention a combination of codes that would capture the majority of FBO
cases, but do not mention if this combination of codes also capture irrelevant cases. Ideally, the
combination of codes would be tested in a different setting for validation.
Please review this paper.
user
Title: A retrospective cohort study on oesophageal food bolus obstruction in the North Denmark
Region in 2021 - two thirds were never diagnosed with a cause
Version: 2 Date: 13 Sep 2023
Reviewer's report:
This study by Terkelsen et al aims at investigating causes and treatment of food bowel
obstruction (FBO), adherence to clinical guidelines, and usage of diagnostic codes to capture
hospital visits for FBO.  The authors conclude that the causes of FBO were rarely found and that
adherence to clinical guidelines recommending gastroscopy was low. Comments to consider:
1. Suggest that the authors consult STROBE guidelines to strengthen the structure of the
manuscript.
2. It is unclear from the introduction which gap in the existing evidence this study aims
at addressing. Why is this study relevant for an international audience? What may be new
knowledge here?
3. The study is limited by the fact that it is purely descriptive and only represents a few hospitals.
This fact underlines the need for the authors to provide a very strong reason why this study
belongs in an international journal.
4. The method section is unclear. Again, the authors should consult STROBE guidelines. For
instance, the design of the study is not mentioned, but is pivotal for the understanding. The
authors have conducted a cross-sectional (also called prevalence) study including both new and
prevalent FBO cases. It is very important to distinguish prevalent from incident FBO cases, but
the authors only do that to a limited extent. All analysis should be stratified by prevalent and
incident FBO cases.
5. The identification of patients by using ICD-10 and procedure codes is not completely
clear. Did the authors use registry data to identify patients? Did they use discharge or referral
codes? Did they only identify patients with acute admission or patients admitted at specific
departments? How many hospital are included? What is meant by “filtered using selected
ICD-10 codes…”? And what is meant by “…and codes for enteroscopy, colonoscopy and
sigmoidoscopy applied were excluded”? Does it mean that cases with relevant ICD-10 codes in
combination with these procedure codes were excluded?
6. The manuscript would be improved substantially by including validation of codes to capture
FBO. The authors mention a combination of codes that would capture the majority of FBO
cases, but do not mention if this combination of codes also capture irrelevant cases. Ideally, the
combination of codes would be tested in a different setting for validation.
assistant