Demographic and Clinical Correlates of Quality of Life Domains in Spinal Cord Injury

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear authors,

Your manuscript is relevant and important in the field of work on improving the quality of life of people with SCI. Please note the following: in the abstract and in line 130 it says that 74% of the participants are male, while in table 1 this number is 75%. It would be good to reconcile this. Also, in Table 1, for data Educational level and Living condition you have 87 participants, and I don't see an explanation anywhere why there is one missing participant.

Comments on the Quality of English Language

Some sentences are missing an article or preposition, so this should be corrected.

Author Response

Reviewer #1

Your manuscript is relevant and important in the field of work on improving the quality of life of people with SCI.

R: We thank the reviewer for appreciating our work

Please note the following: in the abstract and in line 130 it says that 74% of the participants are male, while in table 1 this number is 75%. It would be good to reconcile this. Also, in Table 1, for data Educational level and Living condition you have 87 participants, and I don't see an explanation anywhere why there is one missing participant.

R: Thank you for highlighting these points. We have now reconciled the percentages in the text and table, and added a note to Table 1 to indicate why information on educational level and living conditions was missing for one participant.

Reviewer 2 Report

Comments and Suggestions for Authors

Dear colleagues researchers,

The manuscript addresses a highly relevant topic: quality of life in patients with spinal cord injuries. I consider the study a valuable contribution to the field. My recommendations focus on the following aspects, which could be addressed alongside other reviewer comments:

• The tables present a wealth of interesting data; standardizing their format and clearly highlighting mean values ± SD would improve clarity, particularly in Table 2, where subjects are divided into subcategories. Additionally, ensuring a consistent style across all tables would enhance readability, as the first table appears somewhat different from the others.

• One category of subjects stands out in particular: vulnerable groups (women, individuals living alone, and those with non-cervical injuries). I suggest expanding the discussion section to include additional insights or recommendations regarding interventions tailored for these groups, which would strengthen the practical relevance of the study.

Thank you. Best regards. 

Author Response

Reviewer #2

• The tables present a wealth of interesting data; standardizing their format and clearly highlighting mean values ± SD would improve clarity, particularly in Table 2, where subjects are divided into subcategories. Additionally, ensuring a consistent style across all tables would enhance readability, as the first table appears somewhat different from the others.

R: We thank the reviewer for this suggestion. The format of the tables has now been standardized.

• One category of subjects stands out in particular: vulnerable groups (women, individuals living alone, and those with non-cervical injuries). I suggest expanding the discussion section to include additional insights or recommendations regarding interventions tailored for these groups, which would strengthen the practical relevance of the study.

R: We have now provided additional recommendations in the discussion.

Reviewer 3 Report

Comments and Suggestions for Authors

1. The World Health Organization (WHO) defines quality of life as an individual’s perception of their position in life within the context of the culture and value systems in which they live, and in relation to their goals, expectations, standards, and concerns [2]. The citation is very outdated, and as such, it is recommended to replace it with: Teoli D, Bhardwaj A. Quality Of Life. [Updated 2023 Mar 27]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK536962/?report=classic
2. The introduction is not sufficiently grounded in theory. The suggestion is to add a few more paragraphs that address the main concepts discussed in the paper.
3. The objective of the study should appear as the purpose of the study; please make the same change in the abstract.
4. The last paragraph of the introduction should outline the paper's structure in sections and subsections.
5. The study was approved by the Ethics Committee CE AVEC (protocol no. 46-2021- 92 OSS-AUSLIM). Here, it is mandatory to specify that the study was conducted in accordance with the Declaration of Helsinki, and the Institutional Review Board Statement must specify: The study has complied with the Declaration of Helsinki (DoH)—Ethical Principles for Medical Research Involving Human Participants (1964) and its latest amendments adopted by the 75th General Assembly of the World Medical Association (WMA) in Finland on 19 October 2024.
6. The authors should place greater emphasis on the inclusion and exclusion criteria applied in the study.
7. Subchapter 2.1. Statistical Analysis does not contain a description of the software used for the statistical part.
8. It is recommended that the paper include calculations of sample size, statistical power, or both.
9. Please also include a normality test to assess the data distribution.
10. The paper does not refer to the chosen significance threshold; please remedy this issue as well.
11. Discussions should begin by specifying the paper's purpose and indicating whether it has been accomplished.
12. In the discussion section, please place greater emphasis on comparing the results of this study with other results from similar studies.
13. The limitations subsection should follow this format: 4.1. Limitations of the study and future research directions.
14. The following outdated bibliographic sources should be removed or replaced from the study: 10, 14, 15, and 23.

Comments on the Quality of English Language

Medium revisions to the English language are required.

Author Response

Reviewer #3

1. The World Health Organization (WHO) defines quality of life as an individual’s perception of their position in life within the context of the culture and value systems in which they live, and in relation to their goals, expectations, standards, and concerns [2]. The citation is very outdated, and as such, it is recommended to replace it with: Teoli D, Bhardwaj A. Quality Of Life. [Updated 2023 Mar 27]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK536962/?report=classic

R: Thank you for this comment. We have replaced the reference as suggested.

1. The introduction is not sufficiently grounded in theory. The suggestion is to add a few more paragraphs that address the main concepts discussed in the paper.

R: We have expanded the introduction, as suggested.

1. The objective of the study should appear as the purpose of the study; please make the same change in the abstract.

 

R:  We have changed the term objective to purpose in the introduction and the abstract

1. The last paragraph of the introduction should outline the paper's structure in sections and subsections.

R: We have now outlined the paper’ structure at the end of the introduction. Yet, we are uncertain whether adding this paragraph is consistent with the journal’s style, as the article is not a report or a book.

1. The study was approved by the Ethics Committee CE AVEC (protocol no. 46-2021- 92 OSS-AUSLIM). Here, it is mandatory to specify that the study was conducted in accordance with the Declaration of Helsinki, and the Institutional Review Board Statement must specify: The study has complied with the Declaration of Helsinki (DoH)—Ethical Principles for Medical Research Involving Human Participants (1964) and its latest amendments adopted by the 75th General Assembly of the World Medical Association (WMA) in Finland on 19 October 2024.

R: We have changed the statement as suggested.

1. The authors should place greater emphasis on the inclusion and exclusion criteria applied in the study.

R: Actually, the inclusion and exclusion criteria were not stringent because the survey was conducted on a single day and all patients hospitalized were invited to participate, except when severe conditions precluded participation. We have tried to better clarify this point.

Subchapter 2.1. Statistical Analysis does not contain a description of the software used for the statistical part. It is recommended that the paper include calculations of sample size, statistical power, or both.

R: We have now clarified that the sample size calculation was performed using G*Power 3.1.9.4, Copyright 1992-2019. All the statistical analyses were conducted using IBM SPSS, Version 30.0, IBM Corporation, 1989, 2024. Information on sample size and power has now been included.

 

1. Please also include a normality test to assess the data distribution.

R: We have now specified the normality test used.

1. The paper does not refer to the chosen significance threshold; please remedy this issue as well.

R: We have now specified the level of significance.

9. Discussions should begin by specifying the paper's purpose and indicating whether it has been accomplished.

R: We have included a specific paragraph at the beginning of the discussion, as suggested.

1. In the discussion section, please place greater emphasis on comparing the results of this study with other results from similar studies.

R: We have placed greater emphasis on comparisons with similar studies.

1. The limitations subsection should follow this format: 4.1. Limitations of the study and future research directions.

R: We have used the format suggested.

1. The following outdated bibliographic sources should be removed or replaced from the study: 10, 14, 15, and 23.

R: We have acknowledged the suggestion to replace ref [14] and [21-23] with more updated ones, still we have retained ref. [10] and [15] because one is the first validation study of WHOQOL-BREF in the population with SCI, and the second addresses interference with pain.

Yet, as you suggested, we have replaced other references with more recent ones.

Reviewer 4 Report

Comments and Suggestions for Authors

 Introduction section:

- Lines 46–56: The introduction lacks recent epidemiological data on SCI incidence/prevalence in the Italian or European context. Please add up-to-date statistics (e.g., from the GBD 2019 study already cited or from Italian national registries).

- Lines 56–69: The sentence describing the use of WHOQOL-BREF in various populations belongs in the Methods section (around line 103), as it relates to instrument validation rather than study rationale. Please move accordingly.

- Hypotheses: The main hypothesis is not explicitly stated. Consider adding: “We hypothesized that age, sex, living situation, and injury characteristics would be significantly associated with differences in QoL domains among hospitalized SCI patients.”

 

 Methods section:

- Organization: As suggested, please divide this section into subsections for better readability:

  - 2.1. Study Design and Setting

  - 2.2. Participants and Eligibility Criteria

  - 2.3. Data Collection and Variables

  - 2.4. Quality of Life Assessment (WHOQOL-BREF)

  - 2.5. Statistical Analysis

  - 2.6. Ethical Considerations

- Protocol: The cross-sectional method is well described, but some details are missing to ensure reproducibility (e.g., exact recruitment procedure, conditions for completing the questionnaires).

- Methodological justification: The statistical choices are appropriate, but the justification for the tests used (t-test, ANOVA, regressions) could be more explicit.

- Sample Size Calculation: The absence of a sample size justification or power calculation is a notable omission. Please add: “A power calculation or post-hoc power analysis should be included to justify the sample size of N=88.”

- Test conditions:

• No test of homogeneity of variances for t-tests/ANOVA
• No residual diagnosis for regressions
• Normality Testing: Please specify whether normality tests (e.g., Shapiro–Wilk, Kolmogorov–Smirnov) were performed to guide the choice between parametric and non-parametric tests.

- Regression details:

• Entry/exit criteria for stepwise not specified
• No collinearity check (VIF/tolerance)
• No diagnosis of influential points

- Lack of description of the software used

 

Results section:

- Management of missing values: 6 cases excluded for missing data in the WHOQOL-BREF, but no details on:

• Pattern of missing data
• Exclusion method (listwise vs. pairwise)
• Potential impact on results

- Multiple adjustments:

• Multiple t-tests performed without correction (Bonferroni, FDR)
• Risk of type I error not addressed

- Power analysis:

• No a priori or post-hoc power analysis
• n=88 may be insufficient to detect modest effects with multiple predictors

- Figure Numbering: The figure on page 4 is unnumbered. All figures should be numbered consecutively (Figure 1, 2, 3…) in order of appearance.

- Figure 1 caption: Replace “Patients' rating of overall physical and psychological health” with “Patients' ratings of overall quality of life and physical health” to match the data presented.

- Line 134: Please define “AIS” at first mention: “AIS (American Spinal Injury Association Impairment Scale) grade.”

 

- Table 1:

• Check the totals. E.g., “High school or higher” = 62 (71%), but 62/88 = 70.5%
• Add a footnote defining all abbreviations: “Abbreviations: AIS, American Spinal Injury Association Impairment Scale; IQR, interquartile range; SD, standard deviation.”

- Table 2: The "AIS grade C" row contains dots (.) for missing standard deviations, but the means are reported (33.3, 50.0, 40.6). With n=1, the standard deviation is undefined → should be "N/A" or omitted.

- Figure 2 (page 7): “PHYS” on the Y-axis should be moved or clarified. “Physical QoL Score” would be more informative.

 

 Discussion section:

- Practical Application: Include specific, actionable recommendations for clinical practice based on your results.

- Study Strengths: The authors should explicitly highlight the study’s strengths: national referral center, multidimensional QoL assessment, multivariate analysis. Consider adding a dedicated paragraph.

Author Response

Reviewer #4

 Introduction section:

- Lines 46–56: The introduction lacks recent epidemiological data on SCI incidence/prevalence in the Italian or European context. Please add up-to-date statistics (e.g., from the GBD 2019 study already cited or from Italian national registries).

R: Thank you for this important comment. We have now provided the information requested.

- Lines 56–69: The sentence describing the use of WHOQOL-BREF in various populations belongs in the Methods section (around line 103), as it relates to instrument validation rather than study rationale. Please move accordingly.

R: We have moved the sentence as suggested.

- Hypotheses: The main hypothesis is not explicitly stated. Consider adding: “We hypothesized that age, sex, living situation, and injury characteristics would be significantly associated with differences in QoL domains among hospitalized SCI patients.”

R: We have stated our hypotheses as suggested.

Methods section:

- Organization: As suggested, please divide this section into subsections for better readability:

  - 2.1. Study Design and Setting

  - 2.2. Participants and Eligibility Criteria

  - 2.3. Data Collection and Variables

  - 2.4. Quality of Life Assessment (WHOQOL-BREF)

  - 2.5. Statistical Analysis

  - 2.6. Ethical Considerations

- Protocol: The cross-sectional method is well described, but some details are missing to ensure reproducibility (e.g., exact recruitment procedure, conditions for completing the questionnaires).

- Methodological justification: The statistical choices are appropriate, but the justification for the tests used (t-test, ANOVA, regressions) could be more explicit.

- Sample Size Calculation: The absence of a sample size justification or power calculation is a notable omission. Please add: “A power calculation or post-hoc power analysis should be included to justify the sample size of N=88.”

- Test conditions:

• No test of homogeneity of variances for t-tests/ANOVA
• No residual diagnosis for regressions
• Normality Testing: Please specify whether normality tests (e.g., Shapiro–Wilk, Kolmogorov–Smirnov) were performed to guide the choice between parametric and non-parametric tests.

- Regression details:

• Entry/exit criteria for stepwise not specified
• No collinearity check (VIF/tolerance)
• No diagnosis of influential points

- Lack of description of the software used

 R: We have rearranged and expanded the methods section as suggested.

Results section:

- Management of missing values: 6 cases excluded for missing data in the WHOQOL-BREF, but no details on:

• Pattern of missing data
• Exclusion method (listwise vs. pairwise)
• Potential impact on results

- Multiple adjustments:

• Multiple t-tests performed without correction (Bonferroni, FDR)
• Risk of type I error not addressed

- Power analysis:

• No a priori or post-hoc power analysis
• n=88 may be insufficient to detect modest effects with multiple predictors

- Figure Numbering: The figure on page 4 is unnumbered. All figures should be numbered consecutively (Figure 1, 2, 3…) in order of appearance.

- Figure 1 caption: Replace “Patients' rating of overall physical and psychological health” with “Patients' ratings of overall quality of life and physical health” to match the data presented.

- Line 134: Please define “AIS” at first mention: “AIS (American Spinal Injury Association Impairment Scale) grade.”

- Table 1:

• Check the totals. E.g., “High school or higher” = 62 (71%), but 62/88 = 70.5%
• Add a footnote defining all abbreviations: “Abbreviations: AIS, American Spinal Injury Association Impairment Scale; IQR, interquartile range; SD, standard deviation.”

- Table 2: The "AIS grade C" row contains dots (.) for missing standard deviations, but the means are reported (33.3, 50.0, 40.6). With n=1, the standard deviation is undefined → should be "N/A" or omitted.

- Figure 2 (page 7): “PHYS” on the Y-axis should be moved or clarified. “Physical QoL Score” would be more informative.

 R: We have made the changes requested.

 Discussion section:

- Practical Application: Include specific, actionable recommendations for clinical practice based on your results.

R: We have now provided additional recommendations.

- Study Strengths: The authors should explicitly highlight the study’s strengths: national referral center, multidimensional QoL assessment, multivariate analysis. Consider adding a dedicated paragraph.

R: We have added information on strengths in a specific paragraph, as requested.

 

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

Congratulations to the authors for their hard work during the review stage and in developing this article!

Author Response

Congratulations to the authors for their hard work during the review stage and in developing this article!

R: We thank you for your appreciation of our work.

Reviewer 4 Report

Comments and Suggestions for Authors

Thank you for your response and for taking the comments into consideration. This is a high-quality piece of work. However, by addressing these points the manuscript will be well-positioned for publication:

1. Major Revisions

A. Representativeness and Selection Bias

The study is monocentric, conducted at a national center of excellence (Montecatone). While this ensures high-quality clinical data, it introduces a selection bias (over-representation of males and traumatic injuries). Recommendation: In the Discussion, it is imperative to moderate the generalizability of the findings. Please explicitly state that results might differ for patients treated in less specialized facilities or those with non-traumatic injuries, which are increasingly common in aging populations.

 B. Assistance in Questionnaire Completion

Approximately 58% of patients received assistance to complete the questionnaires. This may introduce social desirability bias or proxy interpretation bias. Recommendation: Please perform (or report if already conducted) a sensitivity analysis to determine if QoL scores differ significantly between independent responders and those who received assistance.

 

C. Discussion on Time Since Injury

The study reports a negative correlation between time since injury and Social QoL. This finding is critical as it contrasts with some longitudinal studies that observe "coping" mechanisms or stabilization over time. Recommendation: Please nuance this section by mentioning that in a hospital setting (as in this study), long-term patients may present with secondary complications that explain this decline, unlike those successfully reintegrated into the community.

 

2. Minor Revisions and Formal Suggestions

• Discussion Structure: The opening paragraph of the Discussion should be a direct synthesis of the main findings (the "take-home message") before proceeding to comparisons with existing literature.
• Statistical Terminology: Avoid the phrase "borderline significant" for a p-value of 0.05. Instead, report the exact p-value and discuss the clinical significance (effect size) rather than relying solely on statistical probability.
• Table Formatting:
  • Table 2: Please address inconsistencies (e.g., cells with dots "." for standard
  • Table 1: The value for "High school or higher" (62/88) should be corrected to 70.5% instead of 71% for improved precision.

Author Response

Thank you for your response and for taking the comments into consideration. This is a high-quality piece of work. However, by addressing these points the manuscript will be well-positioned for publication:

R: We thank the reviewer for the thoughtful comments and for giving us opportunity to improve the paper and clarify the implications of our findings.

Major Revisions

1. Representativeness and Selection Bias

The study is monocentric, conducted at a national center of excellence (Montecatone). While this ensures high-quality clinical data, it introduces a selection bias (over-representation of males and traumatic injuries). Recommendation: In the Discussion, it is imperative to moderate the generalizability of the findings. Please explicitly state that results might differ for patients treated in less specialized facilities or those with non-traumatic injuries, which are increasingly common in aging populations.

R: Thanks for this suggestion. While we agree on stating as a limitation the generalization of the findings to patients treated in less specialised facilities, the over-representation of males and traumatic etiologies is consistent with evidence from other studies carried out in hospital settings. We have therefore reported and discussed the male-to-female ratio in traumatic and non-traumatic SCI.

1. Assistance in Questionnaire Completion

Approximately 58% of patients received assistance to complete the questionnaires. This may introduce social desirability bias or proxy interpretation bias. Recommendation: Please perform (or report if already conducted) a sensitivity analysis to determine if QoL scores differ significantly between independent responders and those who received assistance.

R: Thank you for raising this important point. We have now reported in the results the comparison of the WHOQOL-BREF scores between patients who required assistance and those who did not.

Results indicate that patients requiring assistance had lower levels of physical and social QoL compared with patients who completed the questionnaire independently. This is consistent with the expectation and does not suggest social desirability or proxy interpretation bias. We have added a comment to the discussion on this result.

1. Discussion on Time Since Injury

The study reports a negative correlation between time since injury and Social QoL. This finding is critical as it contrasts with some longitudinal studies that observe "coping" mechanisms or stabilization over time. Recommendation: Please nuance this section by mentioning that in a hospital setting (as in this study), long-term patients may present with secondary complications that explain this decline, unlike those successfully reintegrated into the community.

R: Thank you for this thoughtful comment. We have now added a sentence to the discussion to mention this important point.

Minor Revisions and Formal Suggestions

Discussion Structure: The opening paragraph of the Discussion should be a direct synthesis of the main findings (the "take-home message") before proceeding to comparisons with existing literature.

R: We have rephrased the first paragraph of the discussion to report the take-home message of the paper.

Statistical Terminology: Avoid the phrase "borderline significant" for a p-value of 0.05. Instead, report the exact p-value and discuss the clinical significance (effect size) rather than relying solely on statistical probability.

R: Thank you for this suggestion. We have now changed the terminology as follows:

“Physical health showed a weak negative association with age (r = −0.213, p = 0.05).”

Table Formatting:

Table 2: Please address inconsistencies (e.g., cells with dots "." for standard

R: Thank you for noticing the dot, that has been removed

Table 1: The value for "High school or higher" (62/88) should be corrected to 70.5% instead of 71% for improved precision.

R: As reported in note to the table, there is one patient with a missing value on educational level. Therefore, the denominator is 87 and the percentage is 71% (62/87).