Review for 10.1186/s12876-020-01360-6 (2020)

Reviewer ’s report  
 
Title: Associati on Between Charlson Comorbidity Index and Complications of Endoscopic  
Resection of Gastric Neoplasms in Elderly Patients  
 
Version: 0 Date: 03 Jan 2020  
 
Reviewer's report:  
 
In the present study, the authors reported that CCI score was related to respiratory complications 
of endoscopic resection in elderly patients and suggested that endoscopic resection should be 
performed cautiously in elderly patients with a hig h CCI score to prevent respiratory 
complications.  
 
This study is interesting but there are points to this study which require clarifications or 
modifications.  
 
The primary outcome in this study was procedure - and sedation -related complications. 
Pneumonia and atelectasis were considered respiratory complications in this study.  
 
In the result, post -procedural complications such as atelectasis and pneumonia occurred in 45 
(18.6%) patients. However, there were only 4 patients who had clinical symptoms and were  
treated with antibiotics. Most other patients had no symptom and improved spontaneously during 
the outpatient follow -up period.   
 
Thus, it would be better to exclude the patients with radiologic atelectasis without symptoms or 
need for treatment and just include the patient with pneumonia or atelectasis with symptoms for 
the respiratory complication.  
 
The authors used CCI combined with age in this study. However, age variable was also added on 
multivariate analysis and both "age" and "CCI ≥ 6" were associa ted with respiratory 
complications on multivariate analysis. Thus, CCI (combined with age) and age variable in this 
study might not be independent variables on linear regression analysis. have interaction. Thus, it 
should be better use original CCI (withou t age) for the better analysis.      
 
[Abstract: Results]  
Please check the correct value of "mean patient age"  
(Abstract &amp;  Result: patient demographics) Mean patient age was 78 (range, 75 -88) years.  
(Table 2) Age, yrs, mean ± SD: 78.7 ± 3.2  
 
[Methods: Assessment of CCI scores before endoscopic procedure].  
"Cerebrovascular accident" should be added in the component of CCI.  
 
 
 
 
[Results: Patient demographics &amp;  Table 1]  
Please check the numbers of variables below (Table 1).  
-Number of lesions: 166+75 = 241 (≠242)  
-Macroscopic appearance: 77+175 = 252 (≠242)  
-Histologic findings: please check the variables in this part. "High -grade dysplasia" might be 
deleted.  
 
How many patients were sedated with propofol? Please add the number of patients sedat ed with 
propofol.  
 
[Discussion]  
Please reorganize the "Discussion section" according to the principles below.  
- This section should discuss the implications of the findings in context of existing 
research and highlight limitations of the study.  
- State the shortcommings and limitations of the study.  
 
[Figure 3]  
There was no citation for figure 3 in the manuscript.  
 
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
Unable to assess  
 
Does th e work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
Yes 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
Unable to assess  
 
Are you able to assess any statistics in the manuscript or would you recommend an  
additional statistical review?  
If an additional statistical review is recommended, please specify what aspects require further  
assessment in your comments to  the editors.  
 
I am able to assess the statistics  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Needs some language corrections before being published  
Declaration of competing interests  
Please complete a declaration o f competing interests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an  
organisation that may in any way gain or lose financially from the publication of this  
manuscript, eith er now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose  
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the  
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds  or has applied for patents relating to the content of the manuscript?  
 
5. Do you have any other financial competing inte rests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare that I have no competing interests' 
below.  If your reply is yes to any, please give details below.  
 
I declare t hat I have no competing interests.  
 
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