PONE-D-20-05380

Health service utilization in immigrants with multiple sclerosis

PLOS ONE

Dear Dr. Rotstein,

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2. Thank you for stating the following in the Financial Disclosure section:"This study was funded through grants from the Multiple Sclerosis Society of Canada and the Consortium of Multiple Sclerosis Centers.  The funding sources had no role in study design, data collection, data analysis, data interpretation, or writing of the report. All authors had full access to the data in the study and the corresponding author had the final responsibility for the decision to submit for publication. The sponsors played no role in the study design; in the collection, analysis and interpretation of data; in the writing of the report; or in the decision to submit the report for publication."

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Dalia Rotstein has received research support from the Consortium of Multiple Sclerosis Centers (CMSC), the Multiple Sclerosis Society of Canada, and Roche Canada. She has served as a speaker or consultant for Alexion, Biogen, EMD Serono, Novartis, Roche and Sanofi Aventis.

Ruth Ann Marrie receives research funding from: CIHR, Research Manitoba, Multiple Sclerosis Society of Canada, Multiple Sclerosis Scientific Foundation, Crohn’s and Colitis Canada, National Multiple Sclerosis Society, CMSC and United States Department of Defence. She is supported by the Waugh Family Chair in Multiple Sclerosis.

Karen Tu has received research funding from the Department of Defense United States of America, MaRS Innovation Fund, Canadian Institutes of Health Research (CIHR), Rathlyn Foundation, Canadian Dermatology Foundation, Canadian Rheumatology Association (CRA), Canadian Initiative for Outcomes in Rheumatology Care (CIORA), Toronto Rehab Institute Chair Fund, University of Toronto Practice-Based Research Network (UTOPIAN), PSI Foundation, Cancer Care Ontario (CCO) Clinical Programs & Quality Initiatives, Arthritis Society, McLaughlin Centre Accelerator Grant, MS Society of Canada and Consortium of MS Centers, Ontario SPOR Support Unit, Ontario Institute for Cancer Research (OICR) Health Services Research Program, Vascular Network and Heart and Stroke Foundation of Ontario. She also receives a research scholar award from the Department of Family and Community Medicine at the University of Toronto.

Susan Schultz has nothing to disclose.

Kinwah Fung has nothing to disclose.

Colleen Maxwell has received research funding from the Canadian Institutes of Health Research, P.S.I. Foundation, MS Society of Canada, Consortium of MS Centers, MS Scientific Research Foundation, Ontario Ministry of Health and Long-Term Care-Health System Research Fund, Canadian Frailty Network, Partners for Canadian Consortium on Neurodegeneration in Aging, Network for Aging Research-University of Waterloo. She is supported by a University Research Chair at the University of Waterloo. "

We note that one or more of the authors are employed by a commercial company: H2 Toronto

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The authors have addressed the important topic of disparities in health services utilization for MS between immigrants and non-immigrants, for which there is a dearth of literature. By focusing on a publicly funded healthcare system in which residents have access to universal health insurance without user fees, the authors are able to focus on disparities that persist despite barriers associated with insurance coverage and payment. The manuscript is well-written. The methods and analyses are sound and are well-described and the conclusions are warranted. My main concerns focus on the framing of the manuscript, which right now lacks context and does not provide a sufficient framework for systematically understanding immigrant disparities in health services utilization for MS.

The first sentence in the introduction states that “disparity in health service utilization across sociodemographic groups is an important but poorly studied phenomenon which may influence health outcomes.” This statement does not accurately characterize the disparities literature, as there have been many high-quality health services research studies documenting the presence and correlates of healthcare disparities in utilization across many disease conditions. The author should restructure the introduction to focus more narrowly on the specific gap in the literature that this study addresses: namely examining disparities in health services utilization for neurological diseases (MS, specifically) between immigrants and non-immigrants.

A second issue is that the authors do not discuss, in the introduction, what type(s) of utilization patterns would constitute a disparity indicative of worse MS care. This makes it difficult to understand how to interpret the results. Typically, in disparity research it is clearly stated what would constitute a disparity (e.g., lower rates of kidney transplantation, lower rates of having a certain drug prescribed). The authors should explicitly state this in the introduction, since many PLOS One readers will not be familiar with patterns of utilization associated with high quality care for MS, especially since they examine 5 types of care (hospitalizations, emergency department (ED) visits, outpatient neurology visits, other outpatient specialty visits, and primary care visits) at 3 different time points. It would be helpful to know how one should interpret the meaning of potential disparities for these 5 outcomes overall, and whether this meaning changes based on whether they occurred in the year before diagnosis, the year of diagnosis, and the two years following diagnosis. For example, are higher rates of neurological visits during the post-diagnosis period different, in terms of quality, than higher rates of neurological visits during the pre-diagnosis year? Perhaps a table could be helpful. In the conclusion, the authors state that their findings suggest that immigrants with MS in Ontario, demonstrated “a generally favourable pattern of access to health services with greater use of neurology outpatient care and lower use of emergency department services.” Providing a description, in the introduction, of what a favorable pattern of health services utilization for MS consists of, would make it easier for the reader to interpret the results later and understand how the authors arrived at their conclusions. Along those lines, it would also be helpful to provide an example or examples of what one might learn from these analyses, in terms of how they might improve our understanding of disparities.

A third issue is the lack of a framework, in the introduction, systematically discussing factors that might contribute to disparities between immigrants and non-immigrants. The authors could draw on existing frameworks for presenting this information. This would provide a context for some of their findings that they discuss (such as to why immigrants experience a higher rate of hospitalization in the year of MS diagnosis despite higher use of outpatient neurology). A related point is that, when setting up their study in the introduction, the authors discuss research on racial/ethnic disparities and immigrant disparities without systematically discussing why these two groups’ experiences might differ. It would strengthen the manuscript if the authors discussed specific factors that may contribute to different patterns of disparities in neurological care and MS care for immigrants compared to members of racial and ethnic minority groups.

Related to this, the authors should also be more explicit about why it is useful to focus on disparities within a system of universal health insurance. That is, within such a system, what other factors would be expected to contribute to disparities, for immigrants in general, and for their particular population in Ontario? Along those lines, when presenting their literature review, it would be useful to know whether any of the studies they cite were conducted in systems of universal health insurance.

Minor concern: The authors should replace the term “Caucasian” with white, as the term Caucasian has a problematic history. See Mukhopadhyay, C. C. (2016). Getting rid of the word" Caucasian. Privilege: A Reader, 21.

Reviewer #2: The authors of the manuscript “Health service utilization in immigrants with multiple sclerosis” have written an interesting paper comparing the use of health services in immigrants to Ontario, Canada, compared to long-term residents.

The objectives are clearly defined, and the methods are fitted to answer the research questions. The pros and cons of the paper are mostly satisfactorily discussed. The health system in Canada ensures that the access to health services are universal and without user fees reducing this possible confounder to a minimum. There are however some issues that must be corrected and answered before the paper can be accepted.

1. The socioeconomic status (SES) is roughly defined as the neighbourhood income quintile based on information from the Registered Persons Database of Ontario. SES could be more widely defined as the persons household income, education level, cultural aspects etc. Would it be possible to retrieve more detailed data on the individuals SES? If not, this should be mentioned in the discussion section.

2. The immigrants were identified by electronic IRCC data which captures those arriving in Ontario since 1985. Thus people arriving to Canada from foreign countries before 1985 and later developing MS, would be defined as “long-term residents.” The authors should discuss this issue and eventually how this might affect the results.

3. The first sentence under “Results” refers to Figure 1. This should be corrected to Figure 2.

4. In figure 3, crude rates are given for the health service utilization in immigrants vs. long-term residents, whereas both crude rates and adjusted rates are given in table 2. It should be more clear how the results were affected by these adjustments and if this would alter the conclusions.

5. As the authors mention in the Discussion section, information about prescription of MS drugs is lacking. Different drugs have different side effect and complication rates, including severe reactions that could require hospital admissions. Could possible systematically differences in the prescription of MS drugs between the ethnic groups explain some of the skewness between outpatient visits and hospitalizations?

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Reviewer #1: No

Reviewer #2: No

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Health service utilization in immigrants with multiple sclerosis

PONE-D-20-05380R1

Dear Dr. Rotstein,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

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PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

Reviewer #2: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: (No Response)

Reviewer #2: The authors have answered all questions to my satisfaction and in my view the paper should now be accepted for publication.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

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Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No