Review for 10.1186/s12876-017-0681-y (2017)

Reviewer ’s report  
 
Title:  Trends in Prevalence, Mortality, Health Care Utilization and Health Care Costs of Swiss 
IBD Patients: a claims data based study of the years 2010, 2012 and 2014  
 
Version: 0 Date: 09 Jan 2017 
 
Reviewer:  Traci  Testerman  
 
Reviewer’s report:  
 
This nationwide retrospective study used electronic medical records to study prevalence, 
treatment modalities, and costs of inflammatory bowel disease in Switzerland over a four year 
period using independent, but potentially overlapping cohorts.  The autho rs found increasing 
prevalence and cost of IBD, relative to overall healthcare spending.  
 
Major comments:  
 
1. There is no information on the control group.  Was it simply all other patients?  If not, 
why was it not age -matched with IBD patients?  
 
2. With regard to costs, there is no mention of inflation.  If costs were not adjusted for 
inflation, what was the inflation rate during the period of study?  
 
3. The reasoning for and limitations of the IBD patient identification model could be better 
explained.  It appears that diagnosis codes are only present in records for hospitalized 
patients, but this is not clearly stated.  Justification for choosing or excluding certain 
drugs should be made.  For example, the choice not to use corticosteroid prescr iptions for 
identification of patients is reasonable, but no mention was made until the discussion.   
 
4. The discussion requires revision.  It could be better organized and introductory sentences 
are needed so that the reader knows what points the authors  are trying to make.  
 
5. In the discussion, the relevant data from the present study should be presented alongside 
comparison data rather than requiring the reader to remember the numbers presented in 
the results section.  For example, in the section discu ssing prevalence and mortality rates, 
overall prevalence from the current study is reiterated, but prevalence among children 
and the sex ratios are not.  
 
6. The potential significance of different health insurance plans is not discussed.  In line 
381, it s tates that patients in the managed care model had lower costs; however, fewer 
IBD patients are in managed care and fewer are in high deductible plans, presumably 
because patients are trying to minimize their out of pocket expenses.  If managed care is 
not chosen by sicker patients due to higher out of pocket costs, this could explain why the 
managed care model appears to provide a cost savings.  Some explanation of insurance 
choices available to Swiss patients should be given for those not familiar with the  system.  
 
7. Figures 2 -4:  Significance should be indicated on the graph.  
 
 
Minor comments  
 
1. Line 96: "newly" should be changed to "new".  
 
2. "disease related group" should be changed to "diagnosis related group"  
 
3. Line 507:  One sentence paragraphs sh ould be avoided if possible.  
 
4. Line 519:  Clarification is needed.  It states that information on prescribed medications is 
unavailable for hospitalized patients, then says that corticosteroids are the most 
commonly prescribed medications among hospitali zed patients.  
 
5. Line 704 -705:  What data are being referred to when comparing IBD patients with those 
suffering from other chronic diseases?   
 
6. Line 706:  Quality of life and work productivity were not assessed in this study and it 
does not make sense  to mention them here.  
 
7. Figure 1:  Colors are too hard to differentiate  
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
No 
 
Does the 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.  
 
Yes 
 
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 recommend additional statistical review  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Acceptable  
 
Declaration of competing interests  
Please complete a declaration of 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, either now or in the future?  
 
2. Do you hold any stocks or shares in a n 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 interests?  
 
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 that I have no competing interests  
 
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