PONE-D-23-26883A Structural Equation Modeling to Determine the Pain Severity and Treatment Effect of the Patients with Low Back Pain Attending at Center for the Rehabilitation of the Paralysed, BangladeshPLOS ONE

Dear Dr. Tasnim,

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Additional Editor Comments:

Please rectify the following things:.

Rahman et al. present a study of factors influencing the severity of lower back pain. This is an important topic. The authors managed to collect a reasonably sized dataset in a relatively short amount of time, which is commendable. However, I have several concerns about the analysis and its presentation.

General Comments

The quality of written English is insufficient for publication. There are frequent unusual phrasings and ungrammatical sentences. Sometimes to the extent that the intended meaning becomes difficult to discern. There are too many instances to list, but I’ve provided some examples in the detailed comments below. I would strongly suggest that the authors obtain help editing the manuscript, ideally from a native speaker.

Detailed Comments

Major Comments

1. The presentation of the data collection and analysis is missing important details.

a. Where did the questionnaire used to collect the data for this study originate? Was that developed previously, or was it developed as part of this study? Based on what is presented in the manuscript I suspect the latter. This should be clarified, and if the questionnaire was indeed developed for this study more details on the process used should be provided. How were questions developed and what was done to ensure face validity and content validity?

b. How was the association of individual items and constructs established? There is no mention of an exploratory factor analysis. Was this done?

c. There seems to be very high correlation between Work Stress, Psychological Health, and Pain Severity, suggesting that the factor structure could be improved. Did the authors examine cross-loadings of the items used?

d. It appears that the same dataset may have been used for exploratory and confirmatory factor analysis (if exploratory factor analysis was carried out at all). A rigorous analysis of this type would require that the questionnaire be assessed for validity, exploratory factor analysis is carried out to establish the factor structure (possibly refining the questionnaire to deal with cross-loadings and otherwise problematic items), a new, independent sample is collected to carry out confirmatory factor analysis to establish that the factor structure is appropriate and robust. Then SEM can be used for a more detailed analysis. Much of this is missing from the description in the manuscript. The authors should clarify to what extent the various stages of the process have taken place.

2. It is unclear to me how treatment was coded. It appears that treatment was recorded for four days, and the manuscript claims that the analysis shows that pain changed in response to treatment, but the model does not seem to model change over time. There is no indication that pain severity was recorded more than once.

3. The authors make several claims that are not supported by their data:

a. The claim that “The age group of 39 to 45 years people is more affected by low back pain” (p. 4, lines 70 -71) cannot be supported by the data presented here. The statement implies that 39 – 45-year-olds are more likely to present with LBP. To establish this, a comparison between the age distribution of the target population (everyone who would visit the centre if they were suffering from LBP) and the observed age distribution of patients. This is not possible based on the patient data alone. Similar considerations apply to the other factors examined in the univariate analyses. The authors should be careful how they present these results. The univariate analyses are useful in characterising the sample, but no inference can be drawn from them.

b. Similarly, the claims on p. 8, lines 139 – 141, seem to rely solely on the frequency with which different groups were observed in the sample. Without reference to an appropriate comparator these do not allow any inference about the relative frequency of LBP.

c. The claim that male participants are more affected by LBP than females because they are “less concerned about their health issues than females” (p. 8, lines 137-138) is simply speculation and not supported by the data. While it is valuable to speculate about the reasons underlying the findings of a study to generate hypotheses for future research, they should be presented as such.

4. I’m not convinced by the bivariate analyses. The authors do not explain what analyses were carried out to obtain the p values. There is also no indication whether the reported p values were adjusted for multiple testing. More importantly, If these factors indeed all contribute to pain severity, they should not be considered in isolation. If the authors wish to carry out a cross-sectional analysis like this, a multiple regression model seems more appropriate.

5. When reporting the outcome of statistical tests, specific p values should be reported. It is not sufficient to state p < 0.05.

6. When reporting the outcome of hypothesis tests, the authors say that “the hypothesis was accepted” when they mean that the null hypothesis was rejected. This wording should be changed to avoid confusion.

Minor Comments

7. The abstract states that “The majority of the respondents were married 174(87%), followed by unmarried respondents …”. It is unclear to me that the distribution of marital status in the sample is sufficiently relevant to merit inclusion in the abstract.

8. Table 1 has a column labelled “Latent constructs”. These appear to be short labels for the individual items, not latent constructs.

9. The item descriptions in Table 1 should be re-worded to better conform with standard usage. For example, “pain of badness” should probably be ‘pain intensity’(I think. It is possible that something else is meant here).

10. Table 3 is labelled “Test of reliability and validity” but appears to show results of the bivariate analyses.

11. Typographical and grammatical errors

a. Abstract, Study design: “… the department of the physiotherapy department …” should be either “the department of physiotherapy” or “the physiotherapy department”.

b. Abstract, Conclusion: “Also pain severity of the patients is significantly associated in treatment scheme with strong strength.” Maybe something like “Pain severity is significantly associated with treatment scheme intensity” would work better here. I’m unsure what the different treatment schemes are and whether ‘intensity’ appropriately describes their difference.

c. p. 2, line 7: “subjects experience mild, severe or acute pair which can last from few days to few years” The use of ‘acute’ in this sentence may be inappropriate. Unlike ‘mild’ and ‘severe’, which indicate different levels of severity, it is typically used to indicate sudden and short periods (of often severe) pain, as opposed to chronic pain.

d. P 2. Line 8: “almost 12% and 44% have LBP at any particular time” This should be something like “12% to 44% have LBP at any particular time”.

e. p. 2, lines 12-14: “Some demographic features such as age, gender etc and other some known risk factors for LBP.” Dele the second instance of “some”.

f. P. 2, line 15: “lumber lordships”. I’m not sure what this is supposed to be. My best guess is ‘lumbar lordosis’.

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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: No

Reviewer #2: No

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

Reviewer #1: No

Reviewer #2: No

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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: No

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: No

Reviewer #2: No

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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: Thank you for letting me review this manuscript. I have some comments that need attention before any decision can be made.

ABSTRACT

The abstract should never have reference on tables or on studies. The description of your results lacks objectivity, and you should rewrite it for clarity.

You use abbreviations (BMI, SEM) that were not previously defined.

The conclusion should be more “straight to the point”, and should only focus on the findings of your study.

The keywords should be more of MeSH terms and less on the statistical analysis you performed.

INTRODUCTION

Lines 6-7: not all LBP comes from injuries; acute pain is not severe pain, please rephrase this sentence.

The introduction should be a part of the text in which you describe the problem and the need for your study. However, the need to assess socioeconomic situation, and etc., is not clear in the text. You should rewrite this whole section in order to improve readability and to really focus on what is the novelty of your study – what it really adds to the literature that was not yet studied by other groups. Invest time in this section to lead the reader to the point you are studying.

Most important than that, though, is that your title is about a modelling proposal, but your aim was to assess the effects of LBP treatments to reduce pain. As such, you need to either change your title, or rewrite your aims (which I believe is the case). In the abstract, you comment about several hypothesis, and they should be clearly stated here, right after the aims of the study. And by hypothesis, I mean the study hypothesis, and not the statistical hypothesis you have elaborated.

MATERIALS AND METHODS

You study lacks description of the instruments used to assess pain severity, low back pain index, work condition, work pressure and etc.. You need to describe thoroughly the instruments you used. If you only used open questions or if you developed an instrument, you should describe it so that readers can understand what was actually assessed by you.

The eligibility criteria are not clear: did you assess men and women? How old should they be to be included or excluded? Did you assess if pain was really from a mechanical origin? How was it assessed? How many days of pain they reported? Did you exclude people that reported chronic LBP? What was your criteria of treatment? Any type of treatment was included? How long have they been undergoing treatment? Please add a complete description of the eligibility criteria.

Why a minimum of 4 days of treatment was established? How did you collect data? In person, through an electronic form? Did you perform physical assessments? Please describe better those methods, especially the instruments you used.

RESULTS

You included people from 18 to 87, which I do not think is adequate. Over 20% of your sample is ≥60 years old, and their data should be very different from people aged 18-29 and from people aged 30-59. You need to rethink your inclusion criteria.

What is pain disability index? What is this instrument?

You present a model for the analysis of an instrument, yet, you do not present a single line on this process.

DISCUSSION

You need to discuss your results, and after reading the paper, I do not know if you created a framework to assess treatment effects on people with acute LBP, if you assessed people with acute LBP and checked if physical therapy worked for them, if you checked whether work and education influence on the effects of physical therapy for LBP or if you created an instrument to understand how other factors influence on LBP.

Reviewer #2: Rahman et al. present a study of factors influencing the severity of lower back pain. This is an important topic. The authors managed to collect a reasonably sized dataset in a relatively short amount of time, which is commendable. However, I have several concerns about the analysis and its presentation.

General Comments

The quality of written English is insufficient for publication. There are frequent unusual phrasings and ungrammatical sentences. Sometimes to the extent that the intended meaning becomes difficult to discern. There are too many instances to list, but I’ve provided some examples in the detailed comments below. I would strongly suggest that the authors obtain help editing the manuscript, ideally from a native speaker.

Detailed Comments

Major Comments

1. The presentation of the data collection and analysis is missing important details.

a. Where did the questionnaire used to collect the data for this study originate? Was that developed previously, or was it developed as part of this study? Based on what is presented in the manuscript I suspect the latter. This should be clarified, and if the questionnaire was indeed developed for this study more details on the process used should be provided. How were questions developed and what was done to ensure face validity and content validity?

b. How was the association of individual items and constructs established? There is no mention of an exploratory factor analysis. Was this done?

c. There seems to be very high correlation between Work Stress, Psychological Health, and Pain Severity, suggesting that the factor structure could be improved. Did the authors examine cross-loadings of the items used?

d. It appears that the same dataset may have been used for exploratory and confirmatory factor analysis (if exploratory factor analysis was carried out at all). A rigorous analysis of this type would require that the questionnaire be assessed for validity, exploratory factor analysis is carried out to establish the factor structure (possibly refining the questionnaire to deal with cross-loadings and otherwise problematic items), a new, independent sample is collected to carry out confirmatory factor analysis to establish that the factor structure is appropriate and robust. Then SEM can be used for a more detailed analysis. Much of this is missing from the description in the manuscript. The authors should clarify to what extent the various stages of the process have taken place.

2. It is unclear to me how treatment was coded. It appears that treatment was recorded for four days, and the manuscript claims that the analysis shows that pain changed in response to treatment, but the model does not seem to model change over time. There is no indication that pain severity was recorded more than once.

3. The authors make several claims that are not supported by their data:

a. The claim that “The age group of 39 to 45 years people is more affected by low back pain” (p. 4, lines 70 -71) cannot be supported by the data presented here. The statement implies that 39 – 45-year-olds are more likely to present with LBP. To establish this, a comparison between the age distribution of the target population (everyone who would visit the centre if they were suffering from LBP) and the observed age distribution of patients. This is not possible based on the patient data alone. Similar considerations apply to the other factors examined in the univariate analyses. The authors should be careful how they present these results. The univariate analyses are useful in characterising the sample, but no inference can be drawn from them.

b. Similarly, the claims on p. 8, lines 139 – 141, seem to rely solely on the frequency with which different groups were observed in the sample. Without reference to an appropriate comparator these do not allow any inference about the relative frequency of LBP.

c. The claim that male participants are more affected by LBP than females because they are “less concerned about their health issues than females” (p. 8, lines 137-138) is simply speculation and not supported by the data. While it is valuable to speculate about the reasons underlying the findings of a study to generate hypotheses for future research, they should be presented as such.

4. I’m not convinced by the bivariate analyses. The authors do not explain what analyses were carried out to obtain the p values. There is also no indication whether the reported p values were adjusted for multiple testing. More importantly, If these factors indeed all contribute to pain severity, they should not be considered in isolation. If the authors wish to carry out a cross-sectional analysis like this, a multiple regression model seems more appropriate.

5. When reporting the outcome of statistical tests, specific p values should be reported. It is not sufficient to state p < 0.05.

6. When reporting the outcome of hypothesis tests, the authors say that “the hypothesis was accepted” when they mean that the null hypothesis was rejected. This wording should be changed to avoid confusion.

Minor Comments

7. The abstract states that “The majority of the respondents were married 174(87%), followed by unmarried respondents …”. It is unclear to me that the distribution of marital status in the sample is sufficiently relevant to merit inclusion in the abstract.

8. Table 1 has a column labelled “Latent constructs”. These appear to be short labels for the individual items, not latent constructs.

9. The item descriptions in Table 1 should be re-worded to better conform with standard usage. For example, “pain of badness” should probably be ‘pain intensity’(I think. It is possible that something else is meant here).

10. Table 3 is labelled “Test of reliability and validity” but appears to show results of the bivariate analyses.

11. Typographical and grammatical errors

a. Abstract, Study design: “… the department of the physiotherapy department …” should be either “the department of physiotherapy” or “the physiotherapy department”.

b. Abstract, Conclusion: “Also pain severity of the patients is significantly associated in treatment scheme with strong strength.” Maybe something like “Pain severity is significantly associated with treatment scheme intensity” would work better here. I’m unsure what the different treatment schemes are and whether ‘intensity’ appropriately describes their difference.

c. p. 2, line 7: “subjects experience mild, severe or acute pair which can last from few days to few years” The use of ‘acute’ in this sentence may be inappropriate. Unlike ‘mild’ and ‘severe’, which indicate different levels of severity, it is typically used to indicate sudden and short periods (of often severe) pain, as opposed to chronic pain.

d. P 2. Line 8: “almost 12% and 44% have LBP at any particular time” This should be something like “12% to 44% have LBP at any particular time”.

e. p. 2, lines 12-14: “Some demographic features such as age, gender etc and other some known risk factors for LBP.” Dele the second instance of “some”.

f. P. 2, line 15: “lumber lordships”. I’m not sure what this is supposed to be. My best guess is ‘lumbar lordosis’.

**********

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Reviewer #1: No

Reviewer #2: Yes: Peter Humburg

**********

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Assessing Pain Severity and Treatment Outcomes in Patients with Low Back Pain: A Structural Equation Modeling Approach at the Center for the Rehabilitation of the Paralysed, Bangladesh

PONE-D-23-26883R1

Dear Sanjida Tasnim,

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.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Md. Feroz Kabir, BPT, MPT, MPH, BPED, MPED

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Dear Authors, Your revised manuscript is getting consideration for acceptance, but you need to improve the English grammar thoroughly and submit it within the next 15 days.

Reviewers' comments: