Reviewer’ s report
Title: Predictive Modeling of Disease Burden in Adult-Onset Ulcerative Colitis Using Health
Administrative Data
Version: 0Date: 25 Nov 2018
Reviewer: Glen Doherty
Reviewer's report:
The authors present a study of health administrative data from adults patients with newly
diagnosed UC from a single Canadian centre. The data were analysed with a view to creating amodel predictive of disease burden (either extensive and/or severe UC). The results are interestingbut even the best models performed only fairly in the discrimination of patients with high diseaseburden. The authors take what could be considered an excessively optimistic slant in theirconclusions, given that they do not present any validation data which is the single biggestweakness. Rather than suggesting (as they do in the conclusion of the abstract) that these modelscould be applied in future population based studies I think the conclusion should rather be thatthey need to be applied in other cohorts for validation. I'm concerned that in the records review ofthe Ottawa patient cohort it is not stated how many patients had a prospectively documentedendoscopic Mayo score. If the severity was retrospectively inferred in a high proportion this willundermine confidence in the model. The other big issue, which is touched on but not adequatelydiscussed, is the fact the disease burden of the cohort does not reflect that seen in population basedstudies (only 20% with proctitis, almost 50% with high disease burden); there is huge potential forbias arising and again this underlines the need for the model to undergo validation in arepresentative population based cohort before it can be applied more widely. A few other minor
issues; there are a number of errors where words are duplicated in the text (e.g. Page 5,
linkagelinkage, datadata). On page seven the authors describe that total disease burden is 'acombination of extent and activity' but there is no precise description of how the two metrics arecombined. On page 9, I find the definition of 'high disease burden' confusing; can I suggest forclarity listing each category that is included (e.g. moderate extensive, severe extensive and severeleft sided; correct?). Overall the manuscript is otherwise well written but I think the Discussioncould be shortened.
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
YesDoes the work include the necessary controls?
If not, please specify which controls are required in your comments to the authors.
Unable to assess
Are the conclusions drawn adequately supported by the data shown?
If not, please explain in your comments to the authors.
YesAre 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 furtherassessment in your comments to the editors.
I recommend additional statistical review
Quality of written English
Please indicate the quality of language in the manuscript:
AcceptableDeclaration 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 thismanuscript, either 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 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 have no conflict of interest relevant to this study to declareI agree to the open peer review policy of the journal. I understand that my name will be included
on my report to the authors and, if the manuscript is accepted for publication, my named reportincluding any attachments I upload will be posted on the website along with the authors'responses. I agree for my report to be made available under an Open Access Creative Commons
CC-BY license (http://creativecommons.org/licenses/by/4.0/). I understand that any comments
which I do not wish to be included in my named report can be included as confidential comments
to the editors, which will not be published.
I agree to the open peer review policy of the journal
Reviewer’ s report
Title: Predictive Modeling of Disease Burden in Adult-Onset Ulcerative Colitis Using Health
Administrative Data
Version: 0Date: 25 Nov 2018
Reviewer: Glen Doherty
Reviewer's report:
The authors present a study of health administrative data from adults patients with newly
diagnosed UC from a single Canadian centre. The data were analysed with a view to creating amodel predictive of disease burden (either extensive and/or severe UC). The results are interestingbut even the best models performed only fairly in the discrimination of patients with high diseaseburden. The authors take what could be considered an excessively optimistic slant in theirconclusions, given that they do not present any validation data which is the single biggestweakness. Rather than suggesting (as they do in the conclusion of the abstract) that these modelscould be applied in future population based studies I think the conclusion should rather be thatthey need to be applied in other cohorts for validation. I'm concerned that in the records review ofthe Ottawa patient cohort it is not stated how many patients had a prospectively documentedendoscopic Mayo score. If the severity was retrospectively inferred in a high proportion this willundermine confidence in the model. The other big issue, which is touched on but not adequatelydiscussed, is the fact the disease burden of the cohort does not reflect that seen in population basedstudies (only 20% with proctitis, almost 50% with high disease burden); there is huge potential forbias arising and again this underlines the need for the model to undergo validation in arepresentative population based cohort before it can be applied more widely. A few other minor
issues; there are a number of errors where words are duplicated in the text (e.g. Page 5,
linkagelinkage, datadata). On page seven the authors describe that total disease burden is 'acombination of extent and activity' but there is no precise description of how the two metrics arecombined. On page 9, I find the definition of 'high disease burden' confusing; can I suggest forclarity listing each category that is included (e.g. moderate extensive, severe extensive and severeleft sided; correct?). Overall the manuscript is otherwise well written but I think the Discussioncould be shortened.
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
YesDoes the work include the necessary controls?
If not, please specify which controls are required in your comments to the authors.
Unable to assess
Are the conclusions drawn adequately supported by the data shown?
If not, please explain in your comments to the authors.
YesAre 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 furtherassessment in your comments to the editors.
I recommend additional statistical review
Quality of written English
Please indicate the quality of language in the manuscript:
AcceptableDeclaration 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 thismanuscript, either 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 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 have no conflict of interest relevant to this study to declareI agree to the open peer review policy of the journal. I understand that my name will be included
on my report to the authors and, if the manuscript is accepted for publication, my named reportincluding any attachments I upload will be posted on the website along with the authors'responses. I agree for my report to be made available under an Open Access Creative Commons
CC-BY license (http://creativecommons.org/licenses/by/4.0/). I understand that any comments
which I do not wish to be included in my named report can be included as confidential comments
to the editors, which will not be published.
I agree to the open peer review policy of the journal
Please review this paper.
user
Reviewer’ s report
Title: Predictive Modeling of Disease Burden in Adult-Onset Ulcerative Colitis Using Health
Administrative Data
Version: 0Date: 25 Nov 2018
Reviewer: Glen Doherty
Reviewer's report:
The authors present a study of health administrative data from adults patients with newly
diagnosed UC from a single Canadian centre. The data were analysed with a view to creating amodel predictive of disease burden (either extensive and/or severe UC). The results are interestingbut even the best models performed only fairly in the discrimination of patients with high diseaseburden. The authors take what could be considered an excessively optimistic slant in theirconclusions, given that they do not present any validation data which is the single biggestweakness. Rather than suggesting (as they do in the conclusion of the abstract) that these modelscould be applied in future population based studies I think the conclusion should rather be thatthey need to be applied in other cohorts for validation. I'm concerned that in the records review ofthe Ottawa patient cohort it is not stated how many patients had a prospectively documentedendoscopic Mayo score. If the severity was retrospectively inferred in a high proportion this willundermine confidence in the model. The other big issue, which is touched on but not adequatelydiscussed, is the fact the disease burden of the cohort does not reflect that seen in population basedstudies (only 20% with proctitis, almost 50% with high disease burden); there is huge potential forbias arising and again this underlines the need for the model to undergo validation in arepresentative population based cohort before it can be applied more widely. A few other minor
issues; there are a number of errors where words are duplicated in the text (e.g. Page 5,
linkagelinkage, datadata). On page seven the authors describe that total disease burden is 'acombination of extent and activity' but there is no precise description of how the two metrics arecombined. On page 9, I find the definition of 'high disease burden' confusing; can I suggest forclarity listing each category that is included (e.g. moderate extensive, severe extensive and severeleft sided; correct?). Overall the manuscript is otherwise well written but I think the Discussioncould be shortened.
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
YesDoes the work include the necessary controls?
If not, please specify which controls are required in your comments to the authors.
Unable to assess
Are the conclusions drawn adequately supported by the data shown?
If not, please explain in your comments to the authors.
YesAre 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 furtherassessment in your comments to the editors.
I recommend additional statistical review
Quality of written English
Please indicate the quality of language in the manuscript:
AcceptableDeclaration 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 thismanuscript, either 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 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 have no conflict of interest relevant to this study to declareI agree to the open peer review policy of the journal. I understand that my name will be included
on my report to the authors and, if the manuscript is accepted for publication, my named reportincluding any attachments I upload will be posted on the website along with the authors'responses. I agree for my report to be made available under an Open Access Creative Commons
CC-BY license (http://creativecommons.org/licenses/by/4.0/). I understand that any comments
which I do not wish to be included in my named report can be included as confidential comments
to the editors, which will not be published.
I agree to the open peer review policy of the journal
assistant