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Congratulations!
Yours,
Yoshi
Prof. Yoshinori Marunaka, M.D., Ph.D.
[# PeerJ Staff Note - this decision was reviewed and approved by Jeremy Loenneke, a PeerJ Section Editor covering this Section #]
Title & Abstract
The revisions in the title and abstract are satisfactory. Hence, no further revisions are required.
Introduction
The author addressed previous comments about the importance of test-retest reliability and concurrent validity in measurement instruments. The introduction was revised to clarify these concepts, emphasizing their role in research, clinical practice, and health assessment. The response is satisfactory, and no further comments are needed for this section.
Figures & Tables
In response to our comments, the authors added a graph (Figure 3) to better visualize the differences between the 6MST and 6MWT, replacing the original table. They also renumbered the tables accordingly. The response is satisfactory, and I have no further concerns.
Material and Methods
The author addressed previous comments about equipment details in the Methods section. They clarified the use of the bioimpedance scale and ergometer, adding information on calibration, measurement protocols, and participant instructions. Environmental factors, such as room temperature, were already addressed in prior revisions. The response is satisfactory, and no further comments are needed.
Results
Upon reviewing the Results section, I have no further concerns or comments regarding the initial review's suggested changes.
Discussion
Upon reviewing the discussion section, I have no further concerns or comments regarding the initial review's suggested changes.
Conclusion
In response to the comments, the authors suggested further research on the long-term stability, responsiveness, and patient-centered outcomes of the 6MST, including studies in different hemodialysis populations. The suggestion is satisfactory, but the typo ("diferente" should be "different") was corrected. No additional comments.
None
Please revise your manuscript according to the remaining comments of Reviewer 3.
Yours,
Yoshi
Prof. Yoshinori Marunaka, M.D., Ph.D.
The authors have answered my comments and have also significantly improved their manuscript.
No more comments to add.
No comment
No comment
No comment
Title & Abstract
Upon reviewing the title and abstract again, we have noted the following points relating to the initial reviewer's suggested changes:
• Comment 11: To response my suggestion to add reason for study population, the authors add the information in the purpose section of the abstract. Their response is satisfactory.
• Comment 12: To response my suggestion to clarify why the 6MST might be more suitable over 6MWT, the author add the information in the purpose section (second sentence). Their response is responsible.
• Comment 13: I have suggested to specify the unique aspect of the study. The authors have added the information in the result section.
• Comment 14: To response my suggestion to revise the conclusion, the authors have added a sentence, “The 6MST provides a feasible, reliable assessment option for hemodialysis patients and could be easily implemented in clinics lacking space and specialized equipment.” It is satisfactory.
• Comment 15: To response my suggestion for adding a brief mention of study limitations and future research plans that explore the 6MST’s applicability in diverse patient populations, the authors add a sentence in the conclusion of the abstract. It is satisfactory.
• There is no additional comment for the abstract.
Introduction
The authors have effectively addressed all major concerns. Overall, the changes made in response to our feedback have improved the manuscript considerably. Please see my feedback for your manuscript.
Upon reviewing the Introduction again, I have noted the following points relating to the initial review's suggested changes:
• Comment 16: I have suggested to briefly discuss how improving functional assessment in hemodialysis patients could influence clinical outcomes. To response my comment, the authors add the following sentence in the second paragraph of the introduction. “The impairment of multiple systems combined with symptoms such as fatigue, vascular dysfunction, and functional decline increase the risk of hospitalization”. Their response is satisfactory.
• Comment 17: I have commented that the introduction could do more highlight for validating the 6MST in hemodialysis patients. The authors added a sentence at the fourth paragraph as “its reliability and validity have not yet been established in hemodialysis patients, who may have unique functional limitations.” Their response is satisfactory.
• Comment 18: To response my suggestion to add a brief summary of key findings from studies validating the 6MST in other populations, the authors added the following information in the fourth paragraph of the introduction. “The 6MST has been validated in populations with exercise limitations similar to those imposed by CKD, such as individuals with chronic obstructive pulmonary disease (COPD), interstitial lung disease and heart failure. Additionally, the 6MST shows a good correlation with the 6MWT in hospitalized COPD patients, suggesting that it could potentially replace the 6MWT in hospital settings.” Their response is satisfactory.
• Comment 19: I have suggested to include a few lines or references about why test-retest reliability and concurrent validity are particularly crucial. To response this, the authors add the following information in the introduction. “Measurement instruments play an important role in research, clinical practice, and health assessment. Studies on the quality of these instruments provide evidence on how their measurement properties have been evaluated, helping professionals choose the best tool for use in clinical practice. Reliability and validity are considered key measurement properties. An instrument’s reliability is its ability to consistently reproduce a result over time and across different settings, while its validity indicates how well it measures exactly what it is intended to measure.”Although their response is acceptable. I would like to suggest the followings to enhance clarity: “Measurement instruments are fundamental in research, clinical practice, and health assessment, providing evidence-based insights for clinical decisions. Reliability ensures that an instrument, like 6MST, consistently reproduces results across repeated measurements, which is vital for tracking patient progress over time. Concurrent validity, assessed against the 6MWT, ensures that the 6MST accurately measures functional capacity, a key indicator of physical performance. This is particularly important in hemodialysis settings where space and specialized equipment may be limited. Including reliable and valid tools allows practitioners to make better-informed decisions and optimize patient care. We have clarified this in the revised manuscript with additional references.
• Comment 20: I have suggested to add the additional references that discuss the limitations of the 6MWT in clinical settings. To response this, the authors add the following sentence: ““However, it is costly, unavailable in most centers, especially hemodialysis clinics, and requires specialized staff to administer it test and interpret the results.” It is satisfactory.
• Comment 21: To response my suggestion, the authors have added the following sentence at the end of the introduction: “This study aims to assess the test-retest reliability and concurrent validity of the 6MST in hemodialysis patients, hypothesizing that it will demonstrate high reliability and validity compared to the 6MWT.” It is adequate.
Figures & Tables
• Comment 22: I have suggested more detailed annotations, such as highlighting key data points or providing brief notes that clarify what specific data trends mean in the context of the study. In this revised version, the author response well adding relevant annotations in the figures and tables.
• Comment 23: In response to my suggestion, the authors revised the figures for uniform formatting.
• Comment 24: The authors revised the title of the table 1, as I suggested.
• Comment 25: I have suggested a side-by-side comparison between 6MST and 6MWT in a single table would more clearly display differences between the two tests. To response this, the authors include a table (Table 2). Instead of table, I would like to suggest a graph to enhance visualization.
• Comment 26: I have suggested to clarify and revise the tables 2 and 3. Now, the authors combined the tables 2 and 3 as a single table (Table 2). It is satisfactory.
• Comment 27: I have suggested to specify timing relative to dialysis sessions or control for physiological fluctuations. The authors responded that no minimum or maximum dialysis duration was established as an inclusion criterion for the study, and the limited number of patient meetings (only three), they were unable to monitor dialysis duration for each patient. It is reasonable.
Material and Methods
Upon reviewing the Methods again, I have noted the following points relating to the initial review's
suggested changes:
• Comment 28: I have suggested to include the environmental conditions. Now, the authors stated that “All tests were conducted at the same time of day (afternoon) in an indoor environment to minimize temperature variations and other interferences.” It is acceptable.
• Comment 29: I have provided this comment: “Although the equipment used (e.g., bioimpedance scale, ergometer) is mentioned, the specific details or settings of these tools are not fully clarified. Additional information on equipment settings, if relevant, could enhance reproducibility.’ The authors responded that “The step was positioned on a stable surface to prevent falls and patient discomfort during testing.” My original comment was focused on the need for more detailed information about the specific settings and configurations of the equipment utilized, such as the bioimpedance scale and ergometer. I would like to suggest to add (1) Details such as calibration settings, measurement protocols, and any adjustments made to the equipment during testing. (2) Information on how participants were instructed to use the equipment, including any pre-testing preparations, and (3) Any relevant environmental factors (e.g., room temperature, humidity) that could affect the measurements.
• Comment 30: I have suggested to include a description of any training or calibration sessions. The authors responded that “In addition, the assessors were trained by an experienced professional to carry out the pulmonary function test and administer the assessments.” This response is acceptable.
• Comment 31: I have suggested to specify a procedure for identifying and handling outliers. The authors responded that due to the small sample size and that the goal was to generalize the results, outliners were included in the analysis. For this study, it is reasonable. However, it should be acknowledged in the limitation section of the Discussion.
• Comment 32: I have suggested to include ‘control group.’ The author responded that the study focused solely on evaluating only patients with fistulas in the upper limbs. Thus, control group cannot be included. Their respond is acceptable. However, it should be acknowledgement in the limitation section.
• Comment 33. I have suggested a familiarization session prior to data collection. The authors responded that they did not include it because they chose to follow the design of most validation studies involving functional tests. It is acceptable.
• Comment 34. To response my suggestion, the authors revised the text accordingly as “Assessments were conducted over two non-consecutive days, alternating with hemodialysis sessions.” It is adequate.
• Comment 35: I have suggested to consistently use the space in units. The authors revised it accordingly. It is adequate.
• Comment 36: I have suggested to consistently use the statistical values formatting. The authors revised it accordingly. It is adequate.
Results
Upon reviewing the Results again, I have noted the following points relating to the initial review's suggested changes:
• Comment 37: I have suggested to do subgroup analysis. The authors provided the following: “Additionally, the 6MST demonstrated a significant negative correlation with age (r = -0.72; p < 0.001), suggesting that advancing age is associated with a decreased total step count and, consequently, reduced functional capacity.” Their respond is satisfactory.
• Comment 38: I have suggested to include performance variability among participants. The authors responded that it is impossible to provide because of small sample size and heterogeneous in nature. It is reasonable.
Discussion
Upon reviewing the Discussion again, I have noted the following points relating to the initial review's suggested changes:
• Comment 39: I have suggested to include how regular functional assessments using the 6MST could improve patient outcomes. The authors added the following sentences in the Discussion, ““The 6MST can be used to assess the functional capacity of CKD patients and improve patient outcomes by identifying those at risk, which influences decision-making regarding treatment.” It is acceptable.
• Comment 40: I have suggested to add the impact of learning effect on the test’s reliability. The authors add the following sentence in the discussion. ““Analysis of the learning effect is important because it demonstrates that the 6MST must be performed twice to ensure its reliability.” It is satisfactory.
• Comment 41: I have suggested to add more details on similar studies in the Discussion. The authors added a paragraph. It is satisfactory.
• Comment 42: I have suggested to include physiological response. The authors have included the following sentence: “These finding indicate that it not only challenges cardiovascular endurance but also engages larger muscle groups, which can provide more detailed insights into both the ventilatory and cardiovascular responses to physical stress.” It is adequate.
• Comment 43: In response to my comment to provide potential variability of the test condition, the authors added a paragraph. It is satisfactory.
• Comment 44: In response to my comment to provide more details in the limitation section. The authors stated accordingly. It is adequate.
• Comment 45: I have suggested to include insights on patient tolerance or the practical considerations. The authors responded well and added a paragraph for it.
• Comment 46: I have suggested to include potential impacts on nephrology and chronic disease research. The authors added the following sentence: “These results have potential implications for nephrology and chronic disease research by encouraging the expansion of investigations into similar patient populations.” It is satisfactory.
• Comment 47: In response to my comments to add clinical implication, the author stated that “It should be implemented in accordance with ATS recommendations and is more valuable when combined with additional assessments, such as tests for strength, endurance, and quality of life, providing a more comprehensive assessment of patients' overall condition. Although it lacks further psychometric data, it can still be used for pre and post-physiotherapy comparisons.” Their response is satisfactory.
• Comment 48: I have suggested to include further studies with adequate follow-up period. The authors added the following text in the limitation section of the revised manuscript. “The study could be complemented by a longitudinal follow-up to examine the stability of the 6MST over time. Incorporating follow-up assessments into future investigations could provide more comprehensive insights into the test’s reliability and ability to assess functional capacity in chronic kidney disease patients over time. Further research is needed to explore other 6MST measurement properties and establish it as a robust functional assessment tool for patients with chronic kidney disease.” It is adequate.
• Comment 52: The authors rephrased the text as I have suggested.
Conclusion
• Comment 49: In response to my suggestion to include the practicality of 6MST, the author added the sentence as: “These findings could contribute to better patient assessment, management, and decision-making, improving patient outcomes.” It is enough.
• Comment 50: In response to include further research direction, the authors stated that Additional studies on the long-term stability, responsiveness, and impact of the 6MST on patient-centered outcomes are recommended to improve understanding of its clinical usefulness. Moreover, further research with diferente hemodialysis populations, including those with varying comorbidities or in different clinical settings, is essential to improve the test's applicability and relevance in broader clinical practice.” It is satisfactory. Please correct the typo (“diferente” should be “different”)
• Comment 51: As I suggested, the authors revised the text in the conclusion. It is adequate.
• Comment 52: As I suggested, the authors rephrase the sentence. It is satisfactory.
Please revise your manuscript according to the reviewers' comments.
Yours,
Yoshi
Prof. Yoshinori Marunaka, M.D., Ph.D.
[# PeerJ Staff Note: Reference #21 and #18 are identical. Please check all reference numbers and update accordingly. #]
No comment
The authors performed a cross-sectional study regarding the reliability and validity of 6MWT. They successfully calculated the sample size and enrolled patients based on the inclusion and exclusion criteria. However, the methodology is somehow questionable.
In lines 57-61, they refer to a randomization process. What was that randomization? Since the number of patients is 32, how are patients randomized? Please explain better and add a diagram to illustrate the above randomization process, as well as a flow chart of patients' recruitment process.
No comment
The manuscript is well-structured, clear, and thorough in its reporting of results, context, and data presentation
1) The manuscript is written in professional and clear English, presenting concepts unambiguously and ensuring readability.
2) The manuscript provides adequate references to previous studies on the 6-minute step test (6MST) and the 6-minute walk test (6MWT), covering a sufficient range of populations, including those with COPD and heart failure, as well as their use in exercise tolerance assessment.
3)The manuscript follows a professional structure with clearly defined sections for the introduction, methods, results, discussion, and conclusion. Figures and tables are used effectively to summarize key data and findings, such as sample characteristics and test performance metrics.
4) Raw data and values from the functional tests are shared within the text and tables, providing transparency in the presentation of results.
5) The manuscript is self-contained, presenting all relevant results that directly address the research hypotheses on the reliability and validity of the 6MST in hemodialysis patients. Results are cohesively linked to the hypotheses, and sufficient information is provided to interpret the findings independently, without reliance on additional documents.
Modifications- Introduction. 1) Expand on CKD’s specific impact on functional capacity (e.g., muscle wasting, oxygen utilization)
2) Discuss the impact of repeated hemodialysis sessions on patients' functional capacity, including the cumulative physical strain and fatigue, to highlight the importance of feasible testing options that accommodate these frequent fluctuations in capacity.
3)Address specific limitations of the 6MWT for hemodialysis patients beyond space requirements, such as fatigue and performance variability related to dialysis schedules, to better justify the need for an alternative test
4) Address specific limitations of the 6MWT for hemodialysis patients beyond space requirements, such as fatigue and performance variability related to dialysis schedules, to better justify the need for an alternative test
5) Clarify why validation of the 6MST in populations with similar exercise limitations, like COPD patients, supports its potential application in CKD. This would strengthen the rationale for using the 6MST with hemodialysis patients.
1) The manuscript presents original primary research that aligns with the journal's focus on clinical studies in chronic disease populations. It addresses functional assessment methods specific to hemodialysis patients, a topic of clinical importance and relevance.
2) The research question is well defined, focusing on the reliability and validity of the 6-minute step test (6MST) for assessing functional capacity in hemodialysis patients.
3)The study was conducted with rigorous adherence to ethical and technical standards, including approval from a research ethics committee and informed consent from participants. Exclusion and inclusion criteria were thoughtfully established to ensure the safety of participants and the reliability of results. The study design also incorporates established test-retest protocols to verify reliability and control for potential biases, which strengthens the validity of the findings.
4)The methodology is described with sufficient detail, covering test procedures, measurement protocols, and randomization of functional test order. Equipment specifications and assessment criteria are also well documented
Modification: Methodology- 1) Specify if the study was conducted at a single hemodialysis center or multiple centers. 2) Clarify if participants or assessors were blinded to the test order 3) In the sample size calculation section, could you specify the statistical software used to determine the sample size, and provide the reference for the values or assumptions used (e.g., intraclass correlation coefficient of 0.90)? 4)
The findings are valid, supported by strong statistical correlations between the 6MST and 6MWT, high test-retest reliability, and rigorous methodology, indicating that the 6MST is reliable for hemodialysis patients.
Modification: Discussion-1) Adding a summary sentence early in the discussion to outline key findings (e.g., reliability, correlation with 6MWT, practical advantages) could help to reinforce the main contributions of the study upfront. 2) Briefly explain the significance of similar studies (e.g., in COPD) to emphasize how the validation of 6MST in other conditions provides a foundation for its use in CKD.
This study effectively addresses a relevant research question by validating the 6MST for hemodialysis patients, filling a significant knowledge gap in functional assessment tools. Methodology and ethical standards are rigorous, and detailed descriptions ensure replicability. Findings are supported by strong statistical correlations and test-retest reliability, making the 6MST a viable, accessible tool for assessing functional capacity in this population.
The PDF file includes highlighted sections in red that require modification. Each section's modification points are specified in the preceding notes, organized by section for clarity
Title & Abstract
Although the 6MST has been validated for other patient populations (e.g., COPD), this study is one of the first to examine its validity and reliability in hemodialysis patients. By showing that the 6MST has high test-retest reliability and a strong correlation with the 6MWT, the study opens the door for more accessible functional capacity assessments in this specific group. The study highlights how the 6MST, which requires minimal space and equipment, is better suited for environments with physical limitations, like dialysis centers, making it a potentially valuable tool for routine clinical assessments. Although this is an interesting study, it needs to clarifying some points.
Title:
Your current title is appropriate and does not need changes. It effectively conveys the study's focus on the “reliability and validity” assessment of the “six-minute step test” for evaluating functional capacity in hemodialysis patients.
Abstract
Reason for study population should be briefly mentioned. A brief introductory sentence explaining the challenges in assessing functional capacity in hemodialysis patients; for example, a sentence like “Hemodialysis patients often experience functional limitations that are challenging to assess due to equipment and space constraints” could clarify why the study is necessary.
Adding a line to clarify why the 6MST might be more suitable over 6MWT for this population would strengthen the abstract’s introduction. Also, specifying any unique aspects of the study (For example: especially for CKD patients) could strengthen the relevance.
If the learning effect is significant (e.g., a 7% improvement on the second test), briefly mentioning it in the abstract. For example: “A learning effect was observed, with a 7% improvement on retesting.”
The conclusion of the abstract should describe the practical implications, suggesting how clinicians could use the 6MST in routine care for hemodialysis patients. For example: “The 6MST provides a feasible, reliable assessment option for hemodialysis patients and could be easily implemented in clinics lacking space and specialized equipment.”
If word count permits, a brief mention of study limitations and future research plans that explore the 6MST’s applicability in diverse patient populations can be added.
Introduction
• The introduction effectively points out the space and equipment limitations associated with the 6MWT and CPET, which are barriers for many clinical settings, but there are areas where the background information and context could be further enriched. The introduction currently focuses on the limitations of traditional assessments but it could be better to briefly discuss how improving functional assessment in hemodialysis patients could influence clinical outcomes, such as reducing hospitalization rates, improving quality of life, and guiding rehabilitation interventions. This would enhance the importance of the research. For example:
“Hemodialysis patients often experience significant declines in physical function, which can lead to reduced quality of life, increased hospitalizations, and higher mortality rates.”
• The introduction could do more highlight for validating the 6MST in hemodialysis patients. This is especially important if previous studies on the 6MST have focused mainly on other populations (e.g., COPD). Clearly state that this study evaluating the 6MST specifically in a hemodialysis population. For example: “The 6MST has been validated in populations with chronic obstructive pulmonary disease (COPD), its reliability and validity have not yet been established in hemodialysis patients, who may have unique functional limitations.”
• Include a brief summary of key findings from studies validating the 6MST in other populations (e.g., COPD, heart failure) to show that it has reliable psychometric properties and could potentially be applicable in hemodialysis patients.
• Adding a few lines or references about why test-retest reliability and concurrent validity (psychometric properties) are particularly crucial for routine assessments in clinical settings and hemodialysis patients.
• Additional references that discuss the limitations of the 6MWT in clinical settings or the high cost and resource requirements of CPET to strengthen their credibility.
• End the introduction with a concise summary of the study’s aims and hypothesis. For example:
“This study aims to assess the test-retest reliability and concurrent validity of the 6MST in hemodialysis patients, hypothesizing that the 6MST will demonstrate high reliability and validity compared to the 6MWT.”
Overall, the article is clearly written in professional English; however, some inconsistencies and formatting issues remain. The authors should address the provided comments to improve language and clarity.
Figures & Tables
• Some figures could benefit from more detailed annotations, such as highlighting key data points or providing brief notes that clarify what specific data trends mean in the context of the study. Adding annotations could make it easier for key findings at a glance.
• Ensuring uniform formatting (e.g., inconsistent font sizes, alignment, or spacing) across all tables and figures would improve visual consistency, making the data easier to follow and interpret.
• Table 1: Title should be modified. It should be “Characteristics of the study hemodialytic patients.”
• A side-by-side comparison between 6MST and 6MWT in a single table would more clearly display differences between the two tests. Adding a figure or table showing the mean differences in performance between the first and second 6MST sessions could clearly visualized, which could obscure an important finding of the study.
• Title of the Tables 2 and 3 is confusing. Rewrite clarifying the difference between the two. Moreover, in the title of table or figure should not include the abbreviation. For example, “Six-Minute Step Test” rather than “6MST”. I would like to recommend to combine Table 2 and 3 as a single table with four columns for six different groups.
• Hemodialysis patients’ physical condition can vary depending on how recently they’ve undergone dialysis, which affects their performance. However, the study does not specify timing relative to dialysis sessions or control for physiological fluctuations. Including this detail would improve consistency and help control for potential variability due to dialysis.
• The study should mention the environmental conditions (e.g., room temperature, noise levels) and any specific timing during the day for the tests, as these factors could influence patients’ performance and physiological responses.
• Although the equipment used (e.g., bioimpedance scale, ergometer) is mentioned, the specific details or settings of these tools are not fully clarified. Additional information on equipment settings, if relevant, could enhance reproducibility.
• The authors mentioned that tests were conducted by two assessors. In this situation, there could be variability in how instructions were given or how outcomes were recorded. Including a description of any training or calibration sessions for assessors would help ensure consistency and improve reproducibility.
• The data from physical tests like 6MST and 6MWT can sometimes contain outliers due to patient variability in health status. Specifying a procedure for identifying and handling outliers (e.g., using a predefined criterion or sensitivity analysis) would clarify the study's approach to data variability.
• Including a comparison group, perhaps a population without CKD or on peritoneal dialysis, could provide additional information on how the 6MST performs specifically in hemodialysis patients versus other groups.
• Given the noted 7% learning effect, a familiarization session prior to data collection could improve the accuracy of reliability measurements by minimizing learning effects. This could be especially beneficial for patients unfamiliar with physical assessments like the 6MST.
• In the Method section, "The study involved two days of assessments, alternating with hemodialysis (HD) days." should be rewritten as "Assessments were conducted over two non-consecutive days, alternating with hemodialysis sessions." to improve clarity.
• Units of Measurement: Consistently use spaces before units, such as "57 ± 13 years" instead of "57±13 years."
• Formatting of Statistical Values: Use uniform formatting for statistical values, such as "ICC = 0.94" instead of "ICC=0.94.
Results
• The results do not explore how demographic factors like age, gender, or BMI might influence test outcomes. Hemodialysis patients can vary widely in their physical condition, and these variables could impact both test performance and reliability. Including a subgroup analysis or reporting correlations between demographic factors and test results would enhance understanding of the 6MST’s generalizability across different patient profiles.
• Hemodialysis patients often experience fluctuating physical states due to their treatment schedules and comorbidities. The results would be better if included the performance variability among participants and how dialysis timing may have influenced outcomes. Including a measure of variance or standard deviation analysis for individual performance across test sessions would add depth to the reliability findings, highlighting the potential for day-to-day variation in this patient group.
• Please see the comments for tables and figures too.
Discussion
• Expanding the discussion to include how regular functional assessments using the 6MST could improve patient outcomes (e.g., by identifying patients at risk of functional decline or facilitating tailored exercise interventions) and influence clinical decision-making would make the findings more impactful and relevant.
• The discussion briefly mentions a 7% learning effect, but it does not analyze how this might impact the test’s reliability. This is relevant as learning effects could impact the test’s usefulness in a clinical setting. Providing a more thorough analysis of the learning effect and suggesting ways to mitigate it (e.g., through practice tests) would give clinicians a clearer understanding of how to apply the 6MST reliably.
• Although the 6MST has been validated in other populations (e.g., COPD), the discussion could benefit from a more detailed comparison with findings from similar studies, highlighting both the strengths and limitations of using the 6MST with hemodialysis patients.
• The study presents data on physiological responses (e.g., heart rate, blood pressure, perceived exertion) but does not extensively interpret these in relation to the 6MST’s clinical utility. Expanding on how these responses compare to the 6MWT and discussing their relevance to functional assessments in this population would strengthen the results.
• However, there is little discussion about challenges in implementing the 6MST, such as potential variability in test conditions or differences in patient populations that may affect the results. Enhancing the discussion with a deeper exploration of clinical applications, learning effects, limitations, and patient tolerability would make the findings more comprehensive and actionable. These additions would provide a stronger foundation for adopting the 6MST in clinical practice for hemodialysis patients.
• Expanding the limitations section to discuss factors like sample size, variability in patient condition, and environmental constraints would provide a more balanced perspective. Additionally, suggesting future research directions such as longitudinal studies to assess the 6MST’s stability over time, would improve the discussion. Moreover, as a single-center study with a relatively small sample, some caution is warranted regarding generalizability across diverse hemodialysis populations. Mention this point in the limitation of the Discussion section.
• The discussion including insights on patient tolerance or the practical considerations (e.g., space, time, staff resources) and the ease or difficulty of implementing the 6MST in clinical practice would make the findings more applicable and provide a realistic view of its benefits and limitations.
• Expand the discussion to include potential impacts on nephrology and chronic disease research, such as encouraging further investigations into functional capacity assessments for similar patient groups (e.g., chronic heart disease patients or elderly individuals in dialysis units).
• The discussion lacks practical recommendations for clinicians on how to incorporate the 6MST into routine practice. Suggestion: mention specific guidelines, such as recommended intervals for testing (e.g., monthly, quarterly), and discuss how the 6MST could complement other assessments.
• Although it is appropriate for an initial validation study, it could be complemented by a longitudinal follow-up to examine the stability of the 6MST over time. Adding follow-up assessments (e.g., after one month) in future research could provide more comprehensive insights into the test’s reliability over time. Discuss it in the Limitation section.
Conclusion
• The conclusion briefly mentions the practicality of the 6MST but could better connect these findings to broader clinical outcomes, such as potential improvements in patient management, quality of life, or clinical decision-making for hemodialysis patients, would make the conclusion more impactful.
• Additionally, suggesting future studies to evaluate the 6MST’s long-term stability, responsiveness, or impact on patient-centered outcomes would give the conclusion more depth. A closing statement encouraging further research in diverse hemodialysis populations (e.g., those with varying comorbidities or in different clinical settings) would reinforce the study’s impact and relevance to broader clinical practice.
• To strengthen the conclusion for clarity, "The 6MST is reliable and valid for assessing the functional capacity of hemodialysis patients." Should be revised as "The 6MST provides a reliable and valid measure of functional capacity in hemodialysis patients, suitable for routine clinical assessments."
• The study is mostly clear and professional but could benefit from some minor improvements for readability: “psychometric properties” could be clarified with “measurement reliability and validity.”
• Some phrases could be condensed. For instance, “the 6MST was found to be both reliable and valid” could be shortened to “the 6MST is reliable and valid.
no comment
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