PLOS ONE

Subject: Submission of revised manuscript

Utrecht, April 28th 2021

Dear Dr. Emily Chenette,

Thank you for the invitation to revise and resubmit our paper for publication in PLOS ONE. Please find enclosed our revised manuscript entitled: ‘Reliability, validity and discriminability of patient reported outcomes for non-specific low back pain in a nationwide physical therapy registry: a retrospective observational cohort study’.

The feedback of the reviewers was very useful. We have replied to the feedback in a point-by-point response letter including the journal requirements and the feedback from the reviewers, followed by the responses of the authors (see the Appendix). In the manuscript itself, all text revisions are visible using the track changes function of Microsoft Word (using the ‘All Markup’ mode, to keep the line numbers in correspondence with my rebuttal letter).

We hope this revision made our manuscript eligible for publication in PLOS ONE and meets your expectations.

We look forward to your kind consideration of our revised manuscript.

Yours sincerely,

Guus A. Meerhoff, MSc. (corresponding author)

Radboud university medical center, 114 IQ healthcare,

PO Box, 9101

6500 HB Nijmegen, The Netherlands

+ 31 6 48421927 (phone)

 

Appendix: Point by point reply to the stated journal requirements and the feedback of the reviewers

Journal requirements

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

Author’s reply:

We have changed the style of our paper to align it with PLOS ONE’s style requirements.

2. Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

Author’s reply:

We have checked the reference list and added references number 11-15 based on a text passage that was added in the Introduction. See also comment 1 of reviewer 1. [Line 500-511]

11. Mainz J. Defining and classifying clinical indicators for quality improvement. Int J Qual Heal Care. 2003;15(6):523-530. doi:10.1093/intqhc/mzg081

12. Westby MD, Klemm A, Li LC, Jones CA. Emerging Role of Quality Indicators in Physical Therapist Practice and Health Service Delivery. Phys Ther. 2016;96(1):90-100. doi:10.2522/ptj.20150106

13. McGlynn EA, Asch SM. Developing a clinical performance measure. Am J Prev Med. 1998;14(3 SUPPL.):14-21. doi:10.1016/S0749-3797(97)00032-9

14. Centers for Medicare and Medicaid Services. https://www.cms.gov/Medicare/Quality-Initiatives-Patient-Assessment-Instruments/QualityMeasures/index.html. Published 2019. Accessed January 16th 2021

15. Mainz JAN. Developing evidence-based clinical indicators : a state of the art methods primer. Int J Qual Heal Care. 2003;15(supplement I):5-12.

Furthermore we aligned the references with the style of PLOS ONE’s requirements (e.g. stated as a max of six authors per reference). [Line 467-642]

3. We note that you have indicated that data from this study are available upon request. PLOS only allows data to be available upon request if there are legal or ethical restrictions on sharing data publicly. For more information on unacceptable data access restrictions, please see http://journals.plos.org/plosone/s/data-availability#loc-unacceptable-data-access-restrictions.

In your revised cover letter, please address the following prompts:

a) If there are ethical or legal restrictions on sharing a de-identified data set, please explain them in detail (e.g., data contain potentially sensitive information, data are owned by a third-party organization, etc.) and who has imposed them (e.g., an ethics committee). Please also provide contact information for a data access committee, ethics committee, or other institutional body to which data requests may be sent.

b) If there are no restrictions, please upload the minimal anonymized data set necessary to replicate your study findings as either Supporting Information files or to a stable, public repository and provide us with the relevant URLs, DOIs, or accession numbers. For a list of acceptable repositories, please see http://journals.plos.org/plosone/s/data-availability#loc-recommended-repositories.

We will update your Data Availability statement on your behalf to reflect the information you provide.

Author’s reply:

We are happy to be able to share the anonymized dataset with PLOS ONE. This enables us to comply with the important academic FAIR principles. We have added all necessary datasets and syntaxes as Supporting Information files. [Line 652-680]

4. Please include captions for your Supporting Information files at the end of your manuscript, and update any in-text citations to match accordingly. Please see our Supporting Information guidelines for more information: http://journals.plos.org/plosone/s/supporting-information.

Author’s reply:

When aligning the paper with PLOS ONE’s style requirements we have inserted the Supporting Information including its captions in the correct format.

Comments of reviewer 1

Congratulations to the authors for such a good work. I would like to share some comments/seek for some clarification.

1. Suggest authors to expand on the importance and the use of quality indicators (QIs) in health services. It is unclear in the introduction why authors want to identify if the PROMs can discriminate PT practices.

Author’s reply:

Thank you for your suggestion. We have added a paragraph providing a definition of QIs, showing their potential/importance regarding transparency of service delivery in healthcare. See the paraphrased text passage below.

“QIs are “measurement tools, screens, or flags that are used as guides to monitor, evaluate, and improve the quality of patient care, clinical support services, and organizational functions that affect patient outcomes”. 11 (p 524) QIs consist of explicitly defined and measurable items referring to the structures, processes or outcomes of care, 12,13,14 and have the potential to be used to support quality improvement, accountability and to provide transparency of service delivery in healthcare.15” [Line 57-62]

In addition we have added a sentence in the Introduction, explaining why we want to identify if the PROMs can be used to discriminate between PT practices. PROMs are used for the development of QIs since they enable the measurement of health outcomes based on the direct perception of patients and these instruments are recommended in the Clinical Practice Guidelines (CPGs) of KNGF.

“PROMs were chosen for the development of QIs, since they enable the measurement of health outcomes based on the direct perception of patients and these instruments are recommended in the high quality CPGs of KNGF.” [Line 79-81]

2. Table III - Suggest to have the total N in the top row and present the data in the format of N(%). Suggest to use age categories of similar gap, if not, please justify in Materials and methods section.

Author’s reply:

Thank you for your suggestion. We have changed the order of presentation in Table III. For both outcomes (‘Age distribution’ and ‘Gender distribution’) we now first present the total N (PT-practices and patients). In addition we present the data in the suggested format: N (%). [Line 293-297]

Unfortunately we are not able to change the presented age categories because we have used the age categories as used in the selected national reference data. Since we cannot change the age categorisation in this national reference data, we are obliged to use the categorisation as they are presented in their current form. We have provided the following explanation in the Materials and methods section

“The age categories chosen for this study were aligned with those used in the national reference dataset.” [Line 180-181]

3. Table IV, V, VI - how does the difference being derived? For example, mean age difference has a difference in %. Suggest author to include the explanation in "Materials and methods" section.

Author’s reply:

Thank you for your suggestion. In the “Materials and methods” section we have added the sentence as paraphrased below, explaining how we have derived the differences as presented in the Tables IV, V and VI. Since similar differences have been presented in Table III we have also included this explanation for this Table.

“Differences between the created categories were established by calculating the relative differences on the outcomes of the created groups.” [Line 203-205 & 218-220]

In addition we have added a footnote to the Tables, explaining how the differences were derived. [Line 295, 313-314, 319-320, 333]

4. Kindly specify test used to obtain p-values for Table III - VI. Is it t-test or Fisher's exact test?

Author’s reply:

Thanks you for your suggestion. In the text and in the footnotes of the Tables we have specified that we used a t-test to calculate the p-values. [Line 199, 216, 296, 321]

5. Please provide the number of PT practices that were included in the analysis. Authors only described the number of patients .

Author’s reply:

Thank you for your final comment. We have provided the number of PT practices in Table I [Line 273-277], III [Line 293-297], the description of Table IV [Line 308-311] V [ Line 316-322] & VI [Line 331-337]. In addition throughout the text we have described more clearly what data selection was made for each analysis, providing insight why the numbers (of PT practices and patients) differ in the different Tables [Line: 163, 176, 180-181, 225, 265-266, 282, 284-285, 287, 293, 299]

Comments of reviewer 2

Comments to the authors

Manuscript title:

Reliability, validity and discriminability of patient reported outcomes for non-specific low back pain in a nationwide physical therapy registry: a retrospective observational cohort study

Thank you for inviting me to review the manuscript which aimed at testing to what extent health outcomes in patients with non-specific low back pain (NSLBP) collected with PROMs in the national clinical registry of the Royal Dutch Society for Physical Therapy (KNGF) are reliable, valid and able to discriminate between physical therapy practices.

The paper provides background information about successful involvement of patients and physical therapists in a clinical registry in The Netherlands. The authors included data from an impressive number of physical therapy (PT) practices (n=865) and PTs (n=6,560) of patients with NSLBP over a long period of time, between 2013 and 2018. The comprehensive description of included outcome measures in addition to the methods used to answer the research questions were helpful. Findings were described in detail and discussed sufficiently.

This manuscript addresses an important issue for clinicians, researchers and other stakeholders as it demonstrates the importance and value of clinical registries also for formulating appropriate QI's and provides a good example of a practice test to assess the psychometric properties of the collected data. Therefore, it should be of interest to a wide audience.

I have some minor suggestions that could improve the manuscript further.

1. Abstract: The abstract summarizes the study very well. Please just correct “in this next stages of implementation”.

Author’s reply:

Thank you for your correction with regard to this grammatical error. We have changed wording and used “the” instead of “this”. [Line 44]

2. Introduction: The introduction is comprehensive and informs the reader about the importance of clinical registries also for the development of quality indicators. It would be interested how people consented to participate in the registry and if they have to consent only once or multiple times.

Author’s reply:

Thank you for your suggestion to include a description on how the informed consent is obtained from both the patient and the therapist in the Introduction. We have added the following sentence in the Introduction:

“Data are only collected after a one-off informed consent was provided by the patient and their therapist and recorded in the patient file.” [Line 69-70]

Besides adding this sentence in the Introduction we felt our explanation on how the informed consent was obtained, as described in the Materials and methods section, needed some clarification. Therefore we have reworded the initial sentence in the Materials and methods section as paraphrased below:

“Data were only uploaded to the national clinical registry from the EHR-systems if: 1) the patient provided their informed consent for anonymous use of the clinical data from their patient record, and 2) the therapist provided their informed consent on the use of all patient records for which they received an informed consent of the patient.” [Line 111-114]

3. Method: described comprehensively. In this manuscript, acute vs. chronic NSLBP is defined with acute being 0-12 weeks since onset, and chronic >12 weeks. However, definitions of acute and chronic LBP are different, for example in a review provided by Chou et al. where acute NSLBP is defined <4 weeks' duration) while chronic/subacute NSLBP >4 weeks' duration. Please provide a reason for your definition and a reference.

Chou, R., & Huffman, L. H. (2007). Nonpharmacologic therapies for acute and chronic low back pain: a review of the evidence for an American Pain Society/American College of Physicians clinical practice guideline. Annals of internal medicine, 147(7), 492-504.

Author’s reply:

We understand this question. Indeed, in the literature there are different definitions for patients with (sub)acute versus those with chronic NSLBP. We choose to use the definition provided by the paper of Costa et al. since their meta-analysis from 2012 confirmed the hypothesis that there is a difference in the recovery of patients with (sub)acute versus those with chronic complaints. We have added the reference to this paper in the ‘Data collection’ paragraph in the Materials and methods section.

“…the level of chronicity of their complaints was recorded (i.e. (sub)acute vs. chronic, with (sub)acute being 0-12 weeks since onset, and chronic >12 weeks29)…” [Line 118-120]

29. Costa L da CM, Maher CG, Hancock MJ, McAuley JH, Herbert RD, Costa LOP. The prognosis of acute and persistent low-back pain: a meta-analysis. Can Med Assoc J. 2012;184(11):1229-1230. doi:10.1503/cmaj.120627

In addition we decided to be more precise in declaring the included subgroups. In accordance with the paper of Costa et al. we have changed the wording ‘acute’ to ‘(sub)acute’ throughout the entire article.

4. Results: are very well described. The tables provided help to overlook the results, but please look at the formatting of the tables, e.g. upper and lower lines in Table 1 missing. Table III By “total clinical registry” you mean all data of the KNGF’s clinical registry?

Author’s reply:

Thank you for the provided feedback. We have checked the formatting of the Tables and changed the wording of Table III as suggested. [Line 293-297]

5. Discussion: very well written. I liked the idea of “implementation activities” to facilitate the use of the registry.

Line 295 “that the completions of a repeated PROM measurement has no added value for this patient category” should be have…

Author’s reply:

Thank you for your correction with regard to this grammatical error. We have changed wording and used “have” instead of “has”. [Line 368]

6. Further suggestions: Look for double spaces and commas throughout the text (e.g. after “In addition”, “Nevertheless”).

Author’s reply:

Thank you for your final correction. We have deleted all double spaces and added the commas when necessary.