Review History


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Summary

  • The initial submission of this article was received on February 18th, 2025 and was peer-reviewed by 4 reviewers and the Academic Editor.
  • The Academic Editor made their initial decision on May 28th, 2025.
  • The first revision was submitted on June 30th, 2025 and was reviewed by 2 reviewers and the Academic Editor.
  • A further revision was submitted on July 30th, 2025 and was reviewed by 1 reviewer and the Academic Editor.
  • The article was Accepted by the Academic Editor on August 28th, 2025.

Version 0.3 (accepted)

· · Academic Editor

Accept

I am pleased with the authors’ revisions; the manuscript is now ready for proofreading prior to publication.

Reviewer 4 ·

Basic reporting

No further comments.

Experimental design

The authors have addressed my comments.

Validity of the findings

No further comments.

Version 0.2

· · Academic Editor

Minor Revisions

Please note the recommendation from Reviewer 2.

Reviewer 2 ·

Basic reporting

The authors have address my comments.

Experimental design

The authors have address my comments.

Validity of the findings

no comment

Additional comments

no comment

Reviewer 4 ·

Basic reporting

No further comments.

Experimental design

While the authors acknowledge that exploratory and confirmatory factor analyses would be beneficial future directions for verifying the scale's structure and ensuring proper item grouping, this represents a significant limitation of the current study. The four domains constitute the foundational elements of EMFRA's utility; however, without empirical validation of their validity and reliability, the proposed scale remains a theoretical framework rather than a validated instrument ready for clinical application.

Recommendation: The authors should consider conducting preliminary psychometric analyses in the current study or, at minimum, provide a more detailed roadmap for validation studies, including specific sample size requirements and analytical approaches for the proposed factor analyses. This would strengthen the manuscript's contribution and provide clearer guidance for future implementation.

Validity of the findings

No further comments.

Additional comments

N/A

Version 0.1 (original submission)

· · Academic Editor

Major Revisions

**PeerJ Staff Note:** Please ensure that all review, editorial, and staff comments are addressed in a response letter and that any edits or clarifications mentioned in the letter are also inserted into the revised manuscript where appropriate.

Reviewer 1 ·

Basic reporting

Weaknesses:

The abstract does not adequately report specific quantitative findings, limiting immediate understanding of the study's contribution.

In the introduction, the manuscript does not explicitly compare EMFRA with specific existing frailty scales, leaving readers unclear about exactly how EMFRA is innovative or necessary.

Figures and tables are not sufficiently integrated or explained within the main text, reducing their effectiveness in supporting the manuscript’s narrative.

Suggestions for Improvement:

Abstract: Clearly include quantitative outcomes such as consensus percentages or specific items modified/excluded based on expert feedback.

Introduction: Enhance the literature review by explicitly comparing EMFRA with established scales (e.g., Edmonton Frail Scale, Tilburg Frailty Indicator), identifying clearly their limitations that EMFRA addresses.

Figures and Tables: Ensure each figure/table is explicitly referenced and thoroughly discussed in the results section, clearly describing their significance in relation to study outcomes.

Experimental design

Weaknesses:

Insufficient methodological clarity concerning the selection criteria for the Delphi expert panel and the participants for cognitive interviews. This weakens the transparency and reproducibility of the study.

The manuscript lacks explicit justification for the chosen sample sizes for experts, clinicians, and older adults, making the robustness of these samples unclear.

The analytical methods for cognitive interview analysis are inadequately detailed, limiting clarity and replicability.

Suggestions for Improvement:

Expert Panel Selection: Clearly specify the selection criteria for the 15-member expert panel, detailing their professional backgrounds, expertise levels, and how their expertise aligns specifically with the multidimensional aspects of frailty.

Sample Size Justification: Provide explicit rationale for chosen sample sizes for Delphi rounds and cognitive interviews, detailing how these numbers ensure adequate robustness and methodological rigor.

Cognitive Interview Analysis: Provide detailed descriptions of the analytical procedures used during cognitive interviews (e.g., thematic analysis, coding strategies, or software used), ensuring readers understand clearly how feedback informed item modifications.

Validity of the findings

Weaknesses:

Results of item modifications and exclusions following Delphi and cognitive interviews are not explicitly detailed or justified in the main manuscript, limiting transparency.

Comparative analysis with existing frailty scales within the discussion is insufficiently detailed, reducing clarity about EMFRA's validity advantages over previous instruments.

Suggestions for Improvement:

Results Section: Explicitly describe how specific Delphi and cognitive interview feedback led to particular item modifications or exclusions (e.g., provide examples of modifications made to the "Language" or "Fear" items).

Comparative Discussion: Expand the discussion to include explicit comparisons with existing multidimensional frailty scales, clearly explaining EMFRA’s specific strengths or improvements over previous instruments (e.g., improved multidimensionality or content validity).

Additional comments

Conclusion Section: Clearly articulate actionable recommendations for clinical use of EMFRA (e.g., steps for practical integration into geriatric assessments). Provide explicit suggestions for subsequent validation studies (such as longitudinal studies, predictive validity, and reliability assessments).

Limitations: Clearly discuss potential biases from expert selection, cultural specificity, and language considerations, proposing ways future studies could mitigate these biases.

Reviewer 2 ·

Basic reporting

Fierro-Marrero et al. report a multidimensional frailty scale that includes physical function, cognitive function, emotional status and social situation, by incorporating literature review and expert input. Authors claim the novel frailty scale is benefical to Spanish speaking population. The manuscript is well written in English and results are presented well.

For Introduction, I suggest that authors conduct a more comprehensive review of the current knowledge about frailty measurement. There are many papers describing frailty index (accumulation of deficits) in well-established large human population cohort studies, e.g. UKBiobank (Williams et al., 2019). Social frailty index has also been reported (Shah et al., 2023).

Ref:
Williams et al., 2019. A frailty index for UK Biobank participants. J Gerontol A Biol Sci Med Sci. 74(4):582-587

Shah et al., 2023. Social Frailty Index: Development and validation of an index of social attributes predictive of mortality in older adults. PNAS. 120 (7) e2209414120

Experimental design

I am not a clinician and cannot comment on clinical procedures and outcomes. From my end, the individuals involved in the study is at a small scale, thus making it very difficult to reflect the heterogeneity in human aging process.

Validity of the findings

I mentioned those frailty index measurement above. I suggest authors add more information about how the novel frailty scale compared to the exisiting ones. Is there any differences or improvement? Especially, those FI was developed based on a huge population, for instance, UKBiobank is based on ~ 500k individuals, which generally will be considered more reliable.

Reviewer 3 ·

Basic reporting

Avoid using the term elderly. Instead use older adults or older people
Abstract: please highlight the aim of the study at the introduction section
Introduction: please provide the frailty prevalence in Spain and the commonly used tools for assessing frailty
-Highlight the novelty of your tool
-For preliminary version of EMFRA, provide the translated version of the scale
Results
-Table must be self-explanatory. Provide full term of all abbreviation below the tables
-For the result tables, provide the unit. BMI must be written as BMI (kg/m²).
-How was the scoring determined for the EMFRA scale?
Discussion
-reference by Vet 2011 is outdated. Please provide new reference for this
-May discuss the concept of social and cognitive frailty

Experimental design

The study design is suitable

Validity of the findings

the findings of the article is suitable

Reviewer 4 ·

Basic reporting

The manuscript introduces the Multidimensional Frailty Scale (EMFRA) for assessing frailty in older adults across physical, cognitive, emotional, and social domains. The scale was refined through expert validation and cognitive interviews, resulting in EMFRA-P3. The study highlights EMFRA's potential for early frailty identification and intervention, especially in Spanish-speaking populations. The motivation is compelling, with validation from both experts and patients.

To strengthen the manuscript, I suggest including a detailed comparison with existing frailty measurements to emphasize EMFRA's unique contributions and advantages.

Experimental design

Additionally, while the rationale for including various factors in the four domains is clear, conducting exploratory and confirmatory factor analysis would help verify the scale's structure and ensure proper item grouping.

Validity of the findings

Furthermore, it would be beneficial to analyze EMFRA's predictive validity regarding health outcomes such as hospitalization, mortality, or functional decline over time. This would enhance the scale's practical applicability and support its clinical relevance.

Additional comments

N/A

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