Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript addresses a clinically relevant topic and has potential value, particularly because it examines physical performance, muscle strength, frailty, and health-related quality of life in a peri-urban Latin American older population. The cross-sectional design is appropriate for the stated aim, and the use of SPPB, handgrip strength, Fried-related frailty assessment, and SF-36 provides a useful multidimensional perspective. However, several methodological and reporting issues require clarification before the results can be interpreted with confidence.

1. Clarify the construction and interpretation of the overall SF-36 score.
   The manuscript states that the eight SF-36 domain scores were averaged arithmetically to obtain an “overall” score ranging from 0 to 100. Please clarify whether this composite score has been validated for the version of the SF-36 used in this population. If not, it would be more appropriate to describe it explicitly as a study-specific mean of the eight domain scores rather than as a standard overall SF-36 score. This issue is important because this variable is used in both the linear and multinomial regression analyses.

2. Provide a more precise description of the frailty phenotype used.
   The manuscript refers to the Fried phenotype, but several operational definitions appear to differ from the original phenotype, including the definition of weight loss, the assessment of physical activity, and the walking-speed procedure. The exact sex-, BMI-, and/or height-specific cutoffs should be reported for each component, with appropriate references. If the instrument represents a modified or locally adapted Fried phenotype, this should be stated explicitly. This is particularly important because the main descriptive finding is the very high prevalence of pre-frailty (82.6%).

3. Interpret the multinomial regression cautiously because of sparse outcome categories.
   Only 14 participants were classified as robust and 13 as frail, compared with 128 pre-frail participants. The multinomial model nevertheless includes several explanatory variables. These small category sizes may produce unstable estimates and wide confidence intervals. The authors should explicitly acknowledge this limitation and present these analyses as exploratory. A complete statistical reanalysis is not necessarily required, but the strength of the conclusions derived from this model should be moderated.

4. Correct internal inconsistencies between the Highlights, Results, Discussion, and Conclusions.
   The Highlights state that handgrip strength is independently associated with both physical function and overall quality of life, whereas the Results show no independent association with the overall SF-36 score (p = 0.660). In addition, the Discussion states that physical performance and handgrip strength showed a significant relationship with the physical-function domain, although the SPPB was not significantly associated with this domain after adjustment (p = 0.440). These statements should be revised so that they accurately reflect the reported analyses. The duplicated Spanish sentence in the Highlights should also be removed.

5. Expand the limitations regarding sampling and generalizability.
   The sample was selected by convenience from peri-urban areas, 81.9% of participants were women, and the robust and frail subgroups were very small. These characteristics substantially limit the generalizability of both the estimated prevalence of pre-frailty and the regression findings. The Limitations section should explicitly address these issues.

6. Clarify the ethical approval.
   The manuscript states that the project was approved by the Research Committee of the Faculty of Health Sciences, but it does not provide an approval number, protocol identifier, approval date, or clearly state whether this committee functions as the institutional ethics committee for research involving human participants. This information should be added if available.

7. Review the reference numbering and citation-to-claim mapping.
   The Discussion cites references [21] and [22], while the reference list shown in the manuscript appears to end at reference 20. The citation numbering should therefore be checked throughout, and references supporting specific statements about SPPB, frailty reversal, and clinical implications should be verified.

Author Response

Comment 1: Clarify the construction and interpretation of the overall SF-36 score.
The manuscript states that the eight SF-36 domain scores were averaged arithmetically to obtain an “overall” score ranging from 0 to 100. Please clarify whether this composite score has been validated for the version of the SF-36 used in this population. If not, it would be more appropriate to describe it explicitly as a study-specific mean of the eight domain scores rather than as a standard overall SF-36 score. This issue is important because this variable is used in both the linear and multinomial regression analyses.

Response: Thank you for this important observation. We agree that the arithmetic mean of the eight SF-36 domains should not be interpreted as a validated standard SF-36 summary score. We have therefore revised the manuscript throughout and now explicitly refer to this variable as the “study-specific mean of the SF-36 domain scores.”

The Methods section now clarifies that the scores for the eight domains were transformed to a 0–100 scale and that an additional study-specific composite measure was calculated as their arithmetic mean. We also explicitly state that this measure does not represent a validated standard SF-36 summary score and should not be interpreted as equivalent to the Physical Component Summary (PCS) or Mental Component Summary (MCS). Articulo_MDPI

This terminology has also been applied consistently to the linear regression, multinomial regression, Results, Highlights, Discussion, tables, and Conclusions. For example, the Statistical Analysis section now identifies the study-specific mean of the SF-36 domain scores as the explanatory variable used in the multinomial model. Articulo_MDPI

Changes in the revised manuscript: Materials and Methods, “Assessment of Health-Related Quality of Life” and “Statistical Analysis”; Results; Tables 1–3; Discussion; Conclusions; and Highlights.

Comment 2. Provide a more precise description of the frailty phenotype used.
The manuscript refers to the Fried phenotype, but several operational definitions appear to differ from the original phenotype, including the definition of weight loss, the assessment of physical activity, and the walking-speed procedure. The exact sex-, BMI-, and/or height-specific cutoffs should be reported for each component, with appropriate references. If the instrument represents a modified or locally adapted Fried phenotype, this should be stated explicitly. This is particularly important because the main descriptive finding is the very high prevalence of pre-frailty (82.6%).

Response: Thank you for this observation. We have substantially expanded the description of the frailty assessment and now explicitly state that the study used an adaptation of the physical frailty phenotype proposed by Fried et al.

The revised Methods section specifies the five components of the phenotype and clearly distinguishes between the original criteria that were retained and the components that were methodologically adapted. The classification remains 0 criteria = robust, 1–2 criteria = pre-frail, and ≥3 criteria = frail. Articulo_MDPI

For weight loss, we now explicitly indicate that a self-reported loss of more than 3 kg during the previous three months was used and acknowledge that both the threshold and reference period differ from the original Fried phenotype. Articulo_MDPI

For walking speed, the revised manuscript reports the sex- and height-specific cutoffs, and for muscle weakness it reports the sex- and BMI-specific handgrip-strength cutoffs. Articulo_MDPI Articulo_MDPI

For physical activity, we explicitly state that the Reuben Hierarchical Questionnaire was used rather than the original weekly energy-expenditure criterion and therefore identify this component as a methodological adaptation of the original Fried criterion. Articulo_MDPI

In addition, the Results section now explicitly cautions that the very high prevalence of pre-frailty may have been influenced by these adaptations and therefore should not be directly compared with studies applying the original phenotype without modification. Articulo_MDPI

Changes in the revised manuscript: Materials and Methods, “Assessment of Frailty”; Results; and Discussion.

Comment 3: Interpret the multinomial regression cautiously because of sparse outcome categories.
Only 14 participants were classified as robust and 13 as frail, compared with 128 pre-frail participants. The multinomial model nevertheless includes several explanatory variables. These small category sizes may produce unstable estimates and wide confidence intervals. The authors should explicitly acknowledge this limitation and present these analyses as exploratory. A complete statistical reanalysis is not necessarily required, but the strength of the conclusions derived from this model should be moderated.

Response: We agree with the reviewer. The multinomial logistic regression has now been explicitly described as exploratory because of the small numbers of participants in the robust (n = 14) and frail (n = 13) categories compared with the pre-frail group (n = 128).

The Statistical Analysis section now states that effect estimates were interpreted cautiously, with particular attention to the magnitude and width of the 95% confidence intervals. Articulo_MDPI

The Discussion also explicitly acknowledges that this imbalance may have reduced the accuracy and stability of the estimates and that the findings from the multinomial model require confirmation in larger and more balanced samples. Articulo_MDPI

The Conclusions were similarly moderated and now emphasize that the multinomial findings should be regarded as exploratory because of the small robust and frail subgroups. Articulo_MDPI

Changes in the revised manuscript: Statistical Analysis, Discussion, Limitations, and Conclusions.

Comment 4: Correct internal inconsistencies between the Highlights, Results, Discussion, and Conclusions.
The Highlights state that handgrip strength is independently associated with both physical function and overall quality of life, whereas the Results show no independent association with the overall SF-36 score (p = 0.660). In addition, the Discussion states that physical performance and handgrip strength showed a significant relationship with the physical-function domain, although the SPPB was not significantly associated with this domain after adjustment (p = 0.440). These statements should be revised so that they accurately reflect the reported analyses. The duplicated Spanish sentence in the Highlights should also be removed.

Response: Thank you. We carefully reviewed the Highlights, Abstract, Results, Discussion, and Conclusions to ensure consistency with the statistical analyses.

The revised Highlights now state that grip strength was independently and positively associated with the physical functioning domain of the SF-36, but not with the study-specific mean of the SF-36 domain scores. They also state that SPPB performance was not independently associated with either outcome. Articulo_MDPI

The Results now clearly report that handgrip strength was associated with physical functioning after adjustment (B = 0.452; β = 0.166; p = 0.041), whereas the SPPB was not (B = 0.412; β = 0.065; p = 0.440). Neither measure was independently associated with the study-specific mean of the SF-36 domain scores. Articulo_MDPI

The revised Discussion and Conclusions now reflect these findings consistently. Articulo_MDPI Articulo_MDPI

The duplicated Spanish sentence previously present in the Highlights was also removed.

Changes in the revised manuscript: Highlights, Abstract, Results, Discussion, and Conclusions.

Comment 5: Expand the limitations regarding sampling and generalizability.
The sample was selected by convenience from peri-urban areas, 81.9% of participants were women, and the robust and frail subgroups were very small. These characteristics substantially limit the generalizability of both the estimated prevalence of pre-frailty and the regression findings. The Limitations section should explicitly address these issues.

Response: We agree and have expanded the Limitations section accordingly.

The revised manuscript now explicitly acknowledges that the convenience sample recruited from peri-urban communities in Montería cannot be considered representative of the general older adult population in Colombia or other countries. It also highlights the potential influence of sociocultural, ethnic, economic, geographic, and healthcare-access differences on external validity. Articulo_MDPI

We additionally acknowledge the marked predominance of women (81.9%; n = 127) and the resulting limitation in generalizing the findings to older men. The small number of men also prevented sufficiently precise sex-stratified analyses. Articulo_MDPI

Finally, we explicitly discuss the markedly uneven frailty-category distribution—14 robust, 128 pre-frail, and 13 frail participants—and its possible effect on the stability and precision of the multinomial regression estimates. Articulo_MDPI

Changes in the revised manuscript: Discussion and Limitations.

Comment 6: Clarify the ethical approval.
The manuscript states that the project was approved by the Research Committee of the Faculty of Health Sciences, but it does not provide an approval number, protocol identifier, approval date, or clearly state whether this committee functions as the institutional ethics committee for research involving human participants. This information should be added if available.

Response: Thank you for this comment. We have revised the Ethical Considerations section to provide the available institutional approval identifier. The manuscript now states that the study was approved by the Research Committee of the Faculty of Health Sciences at Universidad del Sinú (Institutional Committee Meeting No. 009 of 2026). Articulo_MDPI

The Institutional Review Board Statement has also been revised to identify the approving institutional body consistently.

We have retained the official institutional designation of the approving committee and have avoided assigning it a different ethics-committee title unless explicitly supported by the institutional approval documentation.

Important before you submit this response: if you have the exact approval date, add it both to the manuscript and to this response. The current manuscript provides No. 009 of 2026, but not an exact date.

Comment 7: Review the reference numbering and citation-to-claim mapping.
The Discussion cites references [21] and [22], while the reference list shown in the manuscript appears to end at reference 20. The citation numbering should therefore be checked throughout, and references supporting specific statements about SPPB, frailty reversal, and clinical implications should be verified.

Response: Thank you. We conducted a complete review of the citation numbering and the correspondence between citations and the claims they support.

The reference list has been reorganized and now contains 26 consecutively numbered references. References [21] and [22], which are cited in the Discussion, are now correctly included in the reference list. Articulo_MDPI

We also verified and corrected the references supporting the interpretation of SPPB, frailty identification and reversal, and clinical implications. Specifically, the discussion of SPPB is supported by references [12] and [24], early identification of frailty/pre-frailty by [25], and non-pharmacological approaches to preventing or reversing physical frailty by [26]. Articulo_MDPI The reference list now extends through reference [26]. Articulo_MDPI

Duplicate and incorrectly mapped references were removed or reassigned, and all in-text citations were renumbered according to their order of appearance.

Changes in the revised manuscript: Introduction, Methods, Discussion, and References.

 

Reviewer 2 Report

Comments and Suggestions for Authors

The authors mention STROBE guidelines but don’t provide citation.

Missing citation and version of SPSS used for analysis.

Multiple other areas provide incomplete citations.

The study addresses an important public health issue: the relationship between physical performance, muscle strength, frailty, and health-related quality of life (HRQoL) in older adults, a population segment that is rapidly growing globally.

The literature review could be strengthened by including more recent studies specifically examining the relationship between frailty, HRQoL, and physical performance in community-dwelling older adults.

 

The sample is predominantly female (81.9%), which may skew results and limit applicability to older men. The study should discuss potential gender differences in physical function and quality of life.

There is limited information about generalizability of findings because the study was limited to per-urban population in Columbia, it is not very clear how it would translate to other populations internationally.

There seem to be very high prevalence of pre-frailty in the sample. Please provide additional information about the sample or offer information from the literature explaining such a high prevalence.

The multinomial regression estimates may be affected by a very small subgroup of robust and frail participants, this should be acknowledge in the limitations section,

Frailty assessment is very disorganized and needs more details to further identify cut-off points and operationalization of frailty. Include accurate citation for Fried phenotype evidence.

There is no information if the instruments were validated for Colombian population and whether they were translated or used in English.

Provide clarification regarding specific cut-off values used for grip strength and walking speed classifications within the frailty assessment.

Table 2 – missing confidence intervals alongside regression coefficients.

Discussion – some references are not in English and difficult to confirm if they report information stated.

Abbreviations section has a duplicate title

The author claims to have over 20 citations, but there are only 20 references reported.

Multiple formatting and grammatical errors throughout the manuscript.

Inconsistent use of terminology between “non-frail” and “robust” – choose one and report it consistently throughout.

Author Response

Dear, Thank you for your valuable suggestion.

Comment 1. The authors mention STROBE guidelines but don’t provide citation.

Response: We have added the appropriate citation for the STROBE guidelines in the Methods section. The revised manuscript now states that the study was reported in accordance with the STROBE guidelines for cross-sectional studies, and the corresponding STROBE reference has been included as reference [18].

Comment 2. Missing citation and version of SPSS used for analysis.

Response: We have revised the Statistical Analysis section to specify the software and version used. The manuscript now states that the analyses were performed using IBM SPSS Statistics, version 29 (IBM Corp., Armonk, NY, USA).

Comment 3. Multiple other areas provide incomplete citations.

Response: We conducted a comprehensive review of the in-text citations and reference list. Citation numbering was corrected, incomplete references were completed where possible, duplicate references were removed, and the correspondence between specific claims and supporting references was verified throughout the manuscript. The revised reference list now contains 26 consecutively numbered references.

Comment 4. The study addresses an important public health issue: the relationship between physical performance, muscle strength, frailty, and health-related quality of life (HRQoL) in older adults, a population segment that is rapidly growing globally.

Response: We thank the reviewer for this positive assessment and for recognizing the relevance of the public health issue addressed in our study.

Comment 5. The literature review could be strengthened by including more recent studies specifically examining the relationship between frailty, HRQoL, and physical performance in community-dwelling older adults.

Response: We strengthened the Introduction and Discussion by incorporating more recent evidence examining the relationships among frailty, handgrip strength, physical performance, and health-related quality of life in older adults. Recent studies and reviews published between 2024 and 2026 were added to better contextualize our findings within the current literature. Articulo_MDPI

Comment 6. The sample is predominantly female (81.9%), which may skew results and limit applicability to older men. The study should discuss potential gender differences in physical function and quality of life.

Response: The Limitations section has been expanded to explicitly acknowledge the predominance of women in the sample (81.9%) and the potential influence of sex-related differences in muscle strength, physical performance, and perceived quality of life. We also clarify that the relatively small number of men (n = 28) limited the precision of sex-stratified analyses. Future studies with a more balanced sex distribution are recommended.

Comment 7. There is limited information about generalizability of findings because the study was limited to peri-urban population in Colombia; it is not very clear how it would translate to other populations internationally.

Response: We expanded the Discussion and Limitations sections to more clearly address external validity. The revised manuscript now states that the convenience sample recruited from peri-urban communities in Montería cannot be considered representative of the general older adult population in Colombia or of populations in other countries. We also acknowledge that cultural, socioeconomic, ethnic, environmental, and healthcare-access differences may influence both frailty prevalence and the magnitude of the observed associations.

Comment 8. There seem to be very high prevalence of pre-frailty in the sample. Please provide additional information about the sample or offer information from the literature explaining such a high prevalence.

Response: We agree that the observed prevalence of pre-frailty (82.6%) requires careful interpretation. We expanded the Discussion to compare our findings with previously reported prevalence estimates and to highlight the wide variability observed across populations and settings. In addition, we now explicitly acknowledge that the methodological adaptations made to the Fried phenotype, particularly regarding weight loss and physical activity, may have influenced the distribution of participants across frailty categories and may partially explain the high prevalence observed in our sample.

Comment 9. The multinomial regression estimates may be affected by a very small subgroup of robust and frail participants; this should be acknowledged in the limitations section.

Response: We agree. The manuscript now explicitly acknowledges the small numbers of robust (n = 14) and frail (n = 13) participants compared with the pre-frail group (n = 128). The multinomial logistic regression is now described as exploratory, and the Results, Discussion, Limitations, and Conclusions emphasize the potential instability and reduced precision of these estimates.

Comment 10. Frailty assessment is very disorganized and needs more details to further identify cut-off points and operationalization of frailty. Include accurate citation for Fried phenotype evidence.

Response: We substantially reorganized and expanded the frailty assessment section. The revised manuscript now explicitly identifies the assessment as an adaptation of the physical frailty phenotype proposed by Fried et al., describes all five phenotype components, reports the classification criteria for robust, pre-frail, and frail participants, and clearly distinguishes between the original criteria retained and the components that were methodologically adapted. The original Fried phenotype publication is now appropriately cited.

Comment 11. There is no information if the instruments were validated for Colombian population and whether they were translated or used in English.

Response: We clarified in the Methods section that all questionnaire-based instruments were administered in Spanish. When validated versions for the Colombian population were available, those versions were used. For objective physical-performance tests and measurements, standardized procedures from the original protocols or versions previously used in Colombian populations were followed, as appropriate.

Comment 12. Provide clarification regarding specific cut-off values used for grip strength and walking speed classifications within the frailty assessment.

Response: The revised manuscript now reports the exact cut-off values used for walking speed and handgrip strength. Walking-speed criteria are presented according to sex and height, while grip-strength criteria are presented according to sex and BMI, in accordance with the Fried phenotype thresholds.

Comment 13. Table 2 – missing confidence intervals alongside regression coefficients.

Response: Thank you for identifying this omission. Table 2 has been revised to include the 95% confidence intervals for the adjusted unstandardized regression coefficients (B). The table now reports adjusted B with 95% CI, standardized β, adjusted p-values, bivariate p-values, and correlation coefficients.

Comment 14. Discussion – some references are not in English and difficult to confirm if they report information stated.

Response: We reviewed all references used in the Discussion and verified that the cited sources support the corresponding statements. Where possible, internationally indexed English-language references were prioritized. Some non-English references were retained when they were directly relevant to the specific population or clinical context addressed in the manuscript.

Comment 15. Abbreviations section has a duplicate title.

Response: The duplicated “Abbreviations” heading was removed, and the section now appears only once in the revised manuscript.

Comment 16. The author claims to have over 20 citations, but there are only 20 references reported.

Response: Thank you for identifying this inconsistency. The reference list has been comprehensively revised and now contains 26 consecutively numbered references, including all sources cited in the text. References cited in the Discussion beyond number 20 are now correctly included in the final reference list.

Comment 17. Multiple formatting and grammatical errors throughout the manuscript.

Response: The manuscript underwent a comprehensive language and formatting review. Grammatical inconsistencies, punctuation, terminology, table formatting, decimal notation, section headings, and citation style were revised throughout the document to improve clarity, consistency, and readability.

Comment 18. Inconsistent use of terminology between “non-frail” and “robust” – choose one and report it consistently throughout.

Response: We agree. The terminology has been standardized throughout the manuscript to “robust,” “pre-frail,” and “frail”, consistent with the terminology used for the Fried phenotype classification. The previous use of “non-frail” has been removed.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you for the detailed responses and substantial revision of the manuscript. The authors have satisfactorily addressed the major methodological and interpretive concerns raised in the previous review.

In particular, the SF-36 composite measure is now appropriately defined, the adaptations of the Fried frailty phenotype are clearly described, and the limitations of the multinomial regression are explicitly acknowledged. The inconsistencies between the reported results and their interpretation have also been corrected, while the discussion of sampling limitations and generalizability has been substantially strengthened.

I have no further substantive scientific concerns and support publication of the revised manuscript.