Validation of the COmprehensive Score for Financial Toxicity (COST) in Vietnamese patients with cancer

Binh Thang Tran; Dinh Duong Le; Thanh Gia Nguyen; Minh Tu Nguyen; Minh Hanh Nguyen; Cao Khoa Dang; Dinh Trung Tran

doi:10.1371/journal.pone.0306339

Peer Review History

Original SubmissionApril 8, 2024
15 May 2024 Decision Letter - Le An Pham, Editor PONE-D-24-12510Validation of the Vietnamese Comprehensive Score for Financial Toxicity (COST) in Cancer PatientsPLOS ONE Dear Dr. Tran, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please submit your revised manuscript by Jun 29 2024 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. Please include the following items when submitting your revised manuscript: A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter. If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. 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The PLOS ONE style templates can be found at https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf 2. Please include captions for your Supporting Information files at the end of your manuscript, and update any in-text citations to match accordingly. Please see our Supporting Information guidelines for more information: http://journals.plos.org/plosone/s/supporting-information. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes Reviewer #2: Yes ******** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #2: No ****** 3. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: Yes Reviewer #2: No ****** 4. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: No Reviewer #2: Yes ****** 5. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: The paper offers a comprehensive validation study of the Vietnamese version of the Comprehensive Score for Financial Toxicity (COST) instrument among cancer patients. While the methodology is well-described and the study design seems robust, there are formatting inconsistencies and minor issues that require attention before publication. 1. Throughout the manuscript, there are multiple variations of the term for the Vietnamese version of COST. It is crucial to use only one consistent term for clarity. Please ensure that the same term is used consistently across the entire manuscript. 2. The paragraph format in the statistical analysis section lacks consistency. It is suggested to remove the headings "Descriptive statistics" and "Internal consistency" to maintain coherence. 3. Recheck the format of references and citations to ensure consistency and accuracy. Pay attention to punctuation, capitalization, and formatting style (e.g., APA, MLA) to adhere to journal guidelines. 4. The term "Exploratory factor analysis" is redundant as it has already been explained previously. Consider removing it for clarity and conciseness. 5. Additional Comments: Please double-check for any formatting errors or inconsistencies throughout the manuscript to maintain readability. Reviewer #2: The study “Validation of the Vietnamese Comprehensive Score for Financial Toxicity (COST) in Cancer Patients” was performed by Tran et al. The paper is well-written and showed that the COmprehensive Score for financial Toxicity (COST) demonstrated good internal consistency and The Vietnamese COST is reliable and valid. There were several unclear issues and limitations that need to be addressed: - For the principal component analysis, two factors explained more than 64% of the variance, that a low explanation. With this analysis, you can consider adding more factors to have more than 80% of the variance. - Why did the authors express the COST score by both Mean ± SD and Median? This should be based on the distribution of COST score in each group, normal or non-normal distribution. Please also verify the statistical analysis, which tests were used to analyze the differences of COST score: t-test, ANOVA, Kruskal-Wallis or Mann Whitney? - A linear regression should be performed to understand the contribution of independent variables to the COST score. ****** 6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: No Reviewer #2: Yes: Minh Duc Do ******** [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. https://doi.org/10.1371/journal.pone.0306339.r001
Revision 1
20 May 2024 Author Response Date: May 20th, 2024 Dear Editor and Reviewers We would like to thank the editors and reviewers for their constructive comments and suggestions on our paper. We appreciate their feedback and have incorporated substantial revisions in our revised version. All changes have been highlighted in yellow. Once again, thank you very much. Journal requirement Journal Requirements: When submitting your revision, we need you to address these additional requirements. Reply: We have addressed all the issues raised and made corrections to ensure compliance with journal requirements. The title of study All: We have modified the title of study as “Validation of the COmprehensive Score for Financial Toxicity (COST) in Vietnamese Patients with Cancer” Reviewer 1 Reviewer #1: The paper offers a comprehensive validation study of the Vietnamese version of the Comprehensive Score for Financial Toxicity (COST) instrument among cancer patients. While the methodology is well-described and the study design seems robust, there are formatting inconsistencies and minor issues that require attention before publication. 1. Throughout the manuscript, there are multiple variations of the term for the Vietnamese version of COST. It is crucial to use only one consistent term for clarity. Please ensure that the same term is used consistently across the entire manuscript. Reply 1: We have corrected all the terms used for COST, Financial toxictiy and others statistical analysis. 2. The paragraph format in the statistical analysis section lacks consistency. It is suggested to remove the headings "Descriptive statistics" and "Internal consistency" to maintain coherence. Reply 2: We have modified this part for consistency (page 5-6) Statistical analysis Continuous variables were summarized using means, standard deviations (SD), median, and Interquartile range (IQR). Categorical variables were described using frequencies and percentages. The reliability of the scale was assessed using Cronbach's alpha and McDonald's omega coefficients. A coefficient of 0.7 or higher generally indicates good internal consistency [24]. Construct validity involved two steps including exploratory factor analysis (EFA) and confirmatory structure analysis (CFA). EFA identified underlying factors influencing questionnaire responses. The scree plot and varimax rotation determined the number of factors retained [25]. EFA ensured clear and reliable factors through several strategies: (1) Removing items with low loadings (< 0.4) for minimal contribution; (2) requiring factors to have at least 3 items to capture the underlying construct adequately; (3) Removing items with high cross-loadings (> 0.3) to minimize ambiguity and enhance factor distinction [26]. Bartlett's sphericity test and Kaiser-Meyer-Olkin (KMO) confirmed the suitability of EFA [27, 28]. Building on the initial exploration of the factor structure using EFA (two factors loading was selected), CFA was then employed to assess the validity of the identified factor structure [27, 29]. Several fit indices (Root Mean Square Error of Approximation (RMSEA), Goodness-of-Fit Index (GFI), Comparative Fit Index (CFI), and Adjusted Goodness-of-Fit Index (AGFI)) indicated a good model fit (p < 0.001). Convergent validity was assessed using the Pearson correlation coefficient between the COST score and HRQoL (EQ-5D and EQ VAS). Shapiro-Wilk W test (p-value < 0.001) indicated that the COST score were not normally distributed due to skewness. Therefore, nonparametric tests were used to analyze the differences in COST score by characteristics. The Mann-Whitney U test was used for comparisons between two groups, and the Kruskal-Wallis test was used for comparisons between three or more groups. Additionally, a multivariate quantile regression analysis (at the 50th percentile) was conducted to investigate factors associated with the COST score. All independent variables were included for adjustment in the model. The threshold of a statistically significant level was less than 0.05. Data analysis was performed with Stata software (version 13.4.2) and Amos software (version 22.0). 3. Recheck the format of references and citations to ensure consistency and accuracy. Pay attention to punctuation, capitalization, and formatting style (e.g., APA, MLA) to adhere to journal guidelines. Reply 3: We have checked and corrected all citations and references in compliance with journal requirement. 4. The term "Exploratory factor analysis" is redundant as it has already been explained previously. Consider removing it for clarity and conciseness. Reply 4: Thank you for your thorough review. We have removed duplicate information from the statistical analysis and revised the entire section accordingly. (see reply 2) 5. Additional Comments: Please double-check for any formatting errors or inconsistencies throughout the manuscript to maintain readability. Reply 5: Thank you again for your suggestion. We have carefully reviewed the document and made substantial revisions. Reviewer 2 Reviewer #2: The study “Validation of the Vietnamese Comprehensive Score for Financial Toxicity (COST) in Cancer Patients” was performed by Tran et al. The paper is well-written and showed that the COmprehensive Score for financial Toxicity (COST) demonstrated good internal consistency and The Vietnamese COST is reliable and valid. There were several unclear issues and limitations that need to be addressed: 6. For the principal component analysis, two factors explained more than 64% of the variance, that a low explanation. With this analysis, you can consider adding more factors to have more than 80% of the variance. Reply 6: Thank you for raising a critical point regarding the validation steps. After carefully checking our data and re-analyzing it, we found that achieving over 80% variance requires at least five factors to load. Unfortunately, this is not ideal for our scale with only 11 items. We have addressed this limitation in the discussion section on page 10 to further explain our results. (Page 10) Although, in our data analysis, achieving an explained variance of over 80% requires five factor loadings, which is not ideal for the COST scale with only 11 items. Our final two-factor model demonstrates acceptable fit indices, consistent with the findings of Yu et al in China [15]. These comparisons suggest that the COST likely measures distinct but related constructs relevant to FT in cancer patients. We have coppied output from AMOS for reference Total Variance Explained Component Initial Eigenvalues Extraction Sums of Squared Loadings Rotation Sums of Squared Loadings Total % of Variance Cumulative % Total % of Variance Cumulative % Total % of Variance Cumulative % 1 6.003 54.572 54.572 6.003 54.572 54.572 3.747 34.067 34.067 2 1.135 10.317 64.889 1.135 10.317 64.889 3.390 30.822 64.889 3 .724 6.582 71.471 4 .645 5.863 77.334 5 .566 5.145 82.479 6 .486 4.415 86.894 7 .382 3.472 90.366 8 .346 3.148 93.514 9 .297 2.704 96.218 10 .269 2.443 98.661 11 .147 1.339 100.000 Extraction Method: Principal Component Analysis. 7. Why did the authors express the COST score by both Mean ± SD and Median? This should be based on the distribution of COST score in each group, normal or non-normal distribution. Please also verify the statistical analysis, which tests were used to analyze the differences of COST score: t-test, ANOVA, Kruskal-Wallis or Mann Whitney? Reply 7: Thank you for identifying the issues in our statistical analysis. We have addressed these concerns by revising the statistical method and incorporating the median, IQR (interquartile range), and p-value into Table 1. Statistical method (Page 6): Convergent validity was assessed using the Pearson correlation coefficient between the COST score and HRQoL (EQ-5D and EQ VAS). Shapiro-Wilk W test (p-value < 0.001) indicated that the COST scores were not normally distributed due to skewness. Therefore, nonparametric tests were used to analyze the differences in COST score by characteristics. The Mann-Whitney U test was used for comparisons between two groups, and the Kruskal-Wallis test was used for comparisons between three or more groups. Additionally, a multivariate quantile regression analysis (at the 50th percentile) was conducted to investigate factors associated with the COST score. All independent variables were included for adjustment in the model. The threshold of a statistically significant level was less than 0.05. Data analysis was performed with Stata software (version 13.4.2) and Amos software (version 22.0). Table 1: Chracteristics N (%) COST score Mean±SD Median IQR (25th -75th ) p value* All 300 15.1 (7.3) 13 11-18 Age 0.0747 < 60 152 (50.7) 14.1 (6.2) 13 11-16.5 ≥ 60 148 (49.3) 16.2 (8.2) 14 11-20.5 Mean±SD (Max – Min) 58.5±11.9 Sex 0.0121 Men 208 (69.3) 15.8 (7.8) 14 11-20 Women 92 (30.7) 13.4 (6.0) 13 9.5-17 Education level 0.0030 Less than secondary school 95 (31.7) 13.5 (6.1) 12 11-15 From secondary school and above 205 (68.3) 15.8 (7.8) 14 11-20 Living areas 0.0031 Urban 226 (75.3) 14.3 (6.8) 13 11-17 Rural 74 (24.7) 17.7 (8.3) 15 12-23 Religious 0.288 No 248 (82.7) 15.2 (7.5) 13 11-18 Yes 52 (17.3) 14.4 (6.4) 13 11-17.5 Marital status 0.961 Married 277 (92.3) 15.1 (7.4) 13 11-18 Single/Widow/Dervoce 23 (7.7) 14.7 (7.1) 14 9-19 Occupation 0.0001 Stable income jobs 66 (22.0) 18.8 (9.2) 16.5 13-23 Unstable income jobs 163 (54.3) 13.5 (6.5) 13 10-16 No income 71 (23.7) 15.4 (6) 14 11-19 Economic status 0.0070 Poor 19 (6.3) 11.5 (6.0) 11 8-13 Near poor 24 (8.0) 13.1 (6.2) 12 11-15.5 Average 257 (85.7) 15.6 (7.4) 13 11-19 Health insurance benefits 0.5507 100% 153 (51.0) 15.4 (8.1) 13 11-19 95% 36 (12.0) 15.9 (6.6) 14 11.5-20.5 80% 111 (37.0) 14.4 (6.5) 13 11-17 Type of cancers 0.0252 Oesophagus cancer 39 (13.0) 12.3 (6.0) 12 8-15 Stomach cancer 15 (5.0) 13.3 (3.3) 13 13-16 Colorectal cancer 30 (10.0) 15.9 (7.2) 13 11-22 Liver cancer 32 (10.7) 15.4 (7.1) 15 10-18.5 Biliary/pancreatic cancer 112 (37.3) 16.6 (8.3) 14 11-21 Breast cancer 72 (24.0) 14.2 (6.8) 13 11-15 Stages of cancer 0.343 I 6 (2.0) 12.3 (2.8) 11.5 11-14 II 54 (18.0) 13.8 (7.8) 13 9-18 III 110 (36.7) 15.2 (7.1) 13 11-16 IV 130 (43.3) 15.7 (7.4) 13 11-20 Treatment modality 0.0385 Surgery 4 (1.3) 18.5 (17.4) 12.5 8.5-28.5 Surgery and chemotherapy 153 (51.0) 16.3 (8.0) 14 11-20 Chemotherapy 83 (27.7) 13.2 (5.8) 13 10-16 Radiotherapy 54 (18.0) 15 (6.3) 13 11-17 Palliative care 6 (2.0) 10.5 (4.0) 10.5 8-14 Alcohol use 0.670 Yes 175 (58.3) 14.9 (7.3) 13 11-17 No 125 (41.7) 15.4 (7.4) 13 11-19 Cigarette status 11-17 0.953 Yes 146 (48.7) 14.9 (6.8) 13 10-19 No 154 (51.3) 15.3 (7.8) 13 11-17 8. A linear regression should be performed to understand the contribution of independent variables to the COST score. Reply 8: We appreciate your suggestion once again. To address the skewed distribution of the COST score, we performed a multivariate quantile regression model to identify its predictors. We focused on the 50th percentile (median) of the COST score in this regression analysis. All results are presented in Table 4 and the results section (Page 8). Table 4. A multivariate quantile regression analysis for predictors of COST score. Factors Coefficient [95% CI] p-value Age group (≥ 60 vs. <60) 2.50 -0.12 to 5.12 0.062 Sex (Women vs. Men) -5.96 -10.39 to -1.54 0.008 Education level (From secondary school and above vs.Less than secondary school) 0.39 -2.46 to 3.24 0.786 Residence areas (Rural vs. Urban ) -4.57 -7.41 to 1.73 0.002 Religious (Yes vs. No) -1.50 -4.74 to 1.74 0.363 Marital status (Yes vs. No) 1.11 -3.44 to 5.65 0.632 Occupation (vs. Stable income jobs) Unstable income jobs -5.39 -8.71 to -2.07 0.002 No income -4.64 -8.63 to -0.65 0.023 Family economic status (vs. Poor) Near poor 0.82 -5.58 to 7.23 0.801 Average 2.96 -2.1 to 8.03 0.250 Health insurance copayment (vs. 100%) 95% -4.07 -8.35 to 0.2 0.062 80% -0.86 -3.49 to 1.78 0.522 Types of cancer (vs. Oesophagus cancer) Stomach cancer 1.29 -6.64 to 9.21 0.750 Colorectal cancer 2.68 -3.32 to 8.68 0.380 Liver cancer 3.00 -2.39 to 8.39 0.274 Biliary/pancreatic cancer 2.04 -2.77 to 6.84 0.405 Breast cancer 0.07 -5.66 to 5.8 0.980 Stages of cancer (vs. Stage I) II 4.18 -4.63 to 12.99 0.351 III 4.36 -4.19 to 12.91 0.317 IV 5.11 -3.52 to 13.74 0.245 Treatment modality (vs. Surgery) Surgery and chemotherapy 1.68 -8.87 to 12.23 0.754 Chemotherapy -0.25 -10.8 to 10.3 0.963 Radiotherapy 0.11 -10.85 to 11.06 0.985 Palliative care -5.54 -18.94 to 7.87 0.417 Alcohol use (No vs. Yes) 2.86 -0.64 to 6.36 0.109 Cigarette smoking status (No vs. Yes) 2.36 -0.98 to 5.69 0.165 CI, Confidence Interval Attachments Attachment Submitted filename: 2_1 response to reviewers.docx https://doi.org/10.1371/journal.pone.0306339.r002
27 May 2024 Decision Letter - Le An Pham, Editor PONE-D-24-12510R1Validation of the COmprehensive Score for Financial Toxicity (COST) in Vietnamese Patients with CancerPLOS ONE Dear Dr. Tran, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please submit your revised manuscript by Jul 11 2024 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. Please include the following items when submitting your revised manuscript: A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter. If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols. We look forward to receiving your revised manuscript. Kind regards, Le An Pham, Ph.D,MD Academic Editor PLOS ONE Additional Editor Comments: Please provide a detailed explanation of the revisions made to the document based on the opinions of two reviewers, using line by line format. The reason for utilizing both Stata and Amos in the analysis of exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) is to leverage the unique strengths and capabilities of each software tool. I am confident that STATA has the capability to perform these tasks. Do you believe that the presence of a patient aged 90-95 with an unusual value can significantly affect your results? Please find some english certificate group that can assist you in preparing good english manuscript [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. https://doi.org/10.1371/journal.pone.0306339.r003
Revision 2
7 Jun 2024 Author Response Date: June 7th, 2024 Dear Editor and Reviewers Thank you for your additional comments on our first-round revision. We have incorporated your feedback by merging it with the changes we made in the first round of revisions. Response to comments on May 27th, 2024 – Round 2 Additional Editor Comments: 2.1. Please provide a detailed explanation of the revisions made to the document based on the opinions of two reviewers, using line by line format. Reply 2.1: Thank you for your suggestion. We have added in the second part of this response letter and added page and line format 2. The reason for utilizing both Stata and Amos in the analysis of exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) is to leverage the unique strengths and capabilities of each software tool. I am confident that STATA has the capability to perform these tasks. Reply 2.2: Thank you again for your continued interest in our data analysis. While Stata was initially used for descriptive and multivariate analyses, we have reanalyzed the data using SPSS for consistency, as AMOS is also an SPSS extension. This information has been added on page 7, lines 130-131. 3. Do you believe that the presence of a patient aged 90-95 with an unusual value can significantly affect your results? Reply 2.3: We have reviewed the data on age and found that the group of patients aged 80-95 represents only 1.67% of the total sample (result below). Therefore, we believe this distribution is unlikely to significantly influence our overall data analysis. Age Freq. Percent Cum. 27 1 0.33 0.33 32 2 0.67 1.00 33 1 0.33 1.33 34 2 0.67 2.00 35 2 0.67 2.67 36 1 0.33 3.00 38 5 1.67 4.67 39 5 1.67 6.33 40 7 2.33 8.67 41 1 0.33 9.00 42 6 2.00 11.00 43 3 1.00 12.00 44 2 0.67 12.67 45 3 1.00 13.67 46 4 1.33 15.00 47 6 2.00 17.00 48 4 1.33 18.33 49 7 2.33 20.67 50 9 3.00 23.67 51 5 1.67 25.33 52 6 2.00 27.33 53 8 2.67 30.00 54 9 3.00 33.00 55 11 3.67 36.67 56 10 3.33 40.00 57 13 4.33 44.33 58 12 4.00 48.33 59 7 2.33 50.67 60 8 2.67 53.33 61 10 3.33 56.67 62 12 4.00 60.67 63 10 3.33 64.00 64 12 4.00 68.00 65 12 4.00 72.00 66 13 4.33 76.33 67 15 5.00 81.33 68 7 2.33 83.67 69 6 2.00 85.67 70 8 2.67 88.33 71 5 1.67 90.00 72 8 2.67 92.67 73 5 1.67 94.33 74 1 0.33 94.67 75 3 1.00 95.67 77 1 0.33 96.00 78 1 0.33 96.33 79 3 1.00 97.33 80 3 1.00 98.33 83 2 0.67 99.00 86 2 0.67 99.67 95 1 0.33 100.00 Total 300 100.00 . 4. Please find some english certificate group that can assist you in preparing good english manuscript Reply 2.4. Thank you for your comments on the language of our manuscript. We have addressed them by utilizing a professional English editing service (Editage) during this second round of revisions. Please find the certificate attached. Response to comments on May 15th, 2024 (Editors, reviewer 1 & reviewer 2) – Round 1 The title of study All: We have modified the title of study as “Validation of the COmprehensive Score for Financial Toxicity (COST) in Vietnamese Patients with Cancer”. (page 1, line 1-2) Reviewer 1 Reviewer #1: The paper offers a comprehensive validation study of the Vietnamese version of the Comprehensive Score for Financial Toxicity (COST) instrument among cancer patients. While the methodology is well-described and the study design seems robust, there are formatting inconsistencies and minor issues that require attention before publication. 1. Throughout the manuscript, there are multiple variations of the term for the Vietnamese version of COST. It is crucial to use only one consistent term for clarity. Please ensure that the same term is used consistently across the entire manuscript. Reply 1: We have corrected all the terms used for COST, Financial toxicity and others statistical analysis. 2. The paragraph format in the statistical analysis section lacks consistency. It is suggested to remove the headings "Descriptive statistics" and "Internal consistency" to maintain coherence. Reply 2: We have modified this part for consistency. (page 5-6, line 106-129) Statistical analysis Continuous variables were summarized using means, standard deviations (SD), median, and Interquartile range (IQR). Categorical variables were described using frequencies and percentages. The reliability of the scale was assessed using Cronbach's alpha and McDonald's omega coefficients. A coefficient of 0.7 or higher generally indicates good internal consistency [24]. Construct validity involved two steps including exploratory factor analysis (EFA) and confirmatory structure analysis (CFA). EFA identified underlying factors influencing questionnaire responses. The scree plot and varimax rotation determined the number of factors retained [25]. EFA ensured clear and reliable factors through several strategies: (1) Removing items with low loadings (< 0.4) for minimal contribution; (2) requiring factors to have at least 3 items to capture the underlying construct adequately; (3) Removing items with high cross-loadings (> 0.3) to minimize ambiguity and enhance factor distinction [26]. Bartlett's sphericity test and Kaiser-Meyer-Olkin (KMO) confirmed the suitability of EFA [27, 28]. Building on the initial exploration of the factor structure using EFA (two factors loading was selected), CFA was then employed to assess the validity of the identified factor structure [27, 29]. Several fit indices (Root Mean Square Error of Approximation (RMSEA), Goodness-of-Fit Index (GFI), Comparative Fit Index (CFI), and Adjusted Goodness-of-Fit Index (AGFI)) indicated a good model fit (p < 0.001). Convergent validity was assessed using the Pearson correlation coefficient between the COST score and HRQoL (EQ-5D and EQ VAS). Shapiro-Wilk W test (p-value < 0.001) indicated that the COST score were not normally distributed due to skewness. Therefore, nonparametric tests were used to analyze the differences in COST score by characteristics. The Mann-Whitney U test was used for comparisons between two groups, and the Kruskal-Wallis test was used for comparisons between three or more groups. Additionally, a multivariate quantile regression analysis (at the 50th percentile) was conducted to investigate factors associated with the COST score. All independent variables were included for adjustment in the model. The threshold of a statistically significant level was less than 0.05. 3. Recheck the format of references and citations to ensure consistency and accuracy. Pay attention to punctuation, capitalization, and formatting style (e.g., APA, MLA) to adhere to journal guidelines. Reply 3: We have checked and corrected all citations and references in compliance with journal requirement. 4. The term "Exploratory factor analysis" is redundant as it has already been explained previously. Consider removing it for clarity and conciseness. Reply 4: Thank you for your thorough review. We have removed duplicate information from the statistical analysis and revised the entire section accordingly. (see reply 2, page 6, line 110-129) 5. Additional Comments: Please double-check for any formatting errors or inconsistencies throughout the manuscript to maintain readability. Reply 5: Thank you again for your suggestion. We have carefully reviewed the document and made substantial revisions. Reviewer 2 Reviewer #2: The study “Validation of the Vietnamese Comprehensive Score for Financial Toxicity (COST) in Cancer Patients” was performed by Tran et al. The paper is well-written and showed that the COmprehensive Score for financial Toxicity (COST) demonstrated good internal consistency and The Vietnamese COST is reliable and valid. There were several unclear issues and limitations that need to be addressed: 6. For the principal component analysis, two factors explained more than 64% of the variance, that a low explanation. With this analysis, you can consider adding more factors to have more than 80% of the variance. Reply 6: Thank you for raising a critical point regarding the validation steps. After carefully checking our data and re-analyzing it, we found that achieving over 80% variance requires at least five factors to load. (Page 12, line 162-168) Unfortunately, this is not ideal for our scale with only 11 items. We have addressed this limitation in the discussion section on page 10 to further explain our results. However, in our data analysis, achieving an explained variance of over 80% required five-factor loadings, which is not ideal for the COST scale with only 11 items. Our final two-factor model demonstrated acceptable fit indices consistent with the findings of Yu et al. in China [15]. These comparisons suggest that the COST is likely to measure distinct but related constructs relevant to FT in patients with cancer. (Page 18, line 233-237) We have copied output from AMOS for reference Total Variance Explained Component Initial Eigenvalues Extraction Sums of Squared Loadings Rotation Sums of Squared Loadings Total % of Variance Cumulative % Total % of Variance Cumulative % Total % of Variance Cumulative % 1 6.003 54.572 54.572 6.003 54.572 54.572 3.747 34.067 34.067 2 1.135 10.317 64.889 1.135 10.317 64.889 3.390 30.822 64.889 3 .724 6.582 71.471 4 .645 5.863 77.334 5 .566 5.145 82.479 6 .486 4.415 86.894 7 .382 3.472 90.366 8 .346 3.148 93.514 9 .297 2.704 96.218 10 .269 2.443 98.661 11 .147 1.339 100.000 Extraction Method: Principal Component Analysis. 7. Why did the authors express the COST score by both Mean ± SD and Median? This should be based on the distribution of COST score in each group, normal or non-normal distribution. Please also verify the statistical analysis, which tests were used to analyze the differences of COST score: t-test, ANOVA, Kruskal-Wallis or Mann Whitney? Reply 7: Thank you for identifying the issues in our statistical analysis. We have addressed these concerns by revising the statistical method and incorporating the median, IQR (interquartile range), and p-value into Table 1. Statistical method (Page 6, line 122-129): Convergent validity was assessed using the Pearson correlation coefficient between the COST score and HRQoL (EQ-5D and EQ VAS). Shapiro-Wilk W test (p-value < 0.001) indicated that the COST scores were not normally distributed due to skewness. Therefore, nonparametric tests were used to analyze the differences in COST score by characteristics. The Mann-Whitney U test was used for comparisons between two groups, and the Kruskal-Wallis test was used for comparisons between three or more groups. Additionally, a multivariate quantile regression analysis (at the 50th percentile) was conducted to investigate factors associated with the COST score. All independent variables were included for adjustment in the model. The threshold of a statistically significant level was less than 0.05. Table 1: Chracteristics N (%) COST score Mean±SD Median IQR (25th -75th ) p value* All 300 15.1 (7.3) 13 11-18 Age 0.0747 < 60 152 (50.7) 14.1 (6.2) 13 11-16.5 ≥ 60 148 (49.3) 16.2 (8.2) 14 11-20.5 Mean±SD (Max – Min) 58.5±11.9 Sex 0.0121 Men 208 (69.3) 15.8 (7.8) 14 11-20 Women 92 (30.7) 13.4 (6.0) 13 9.5-17 Education level 0.0030 Less than secondary school 95 (31.7) 13.5 (6.1) 12 11-15 From secondary school and above 205 (68.3) 15.8 (7.8) 14 11-20 Living areas 0.0031 Urban 226 (75.3) 14.3 (6.8) 13 11-17 Rural 74 (24.7) 17.7 (8.3) 15 12-23 Religious 0.288 No 248 (82.7) 15.2 (7.5) 13 11-18 Yes 52 (17.3) 14.4 (6.4) 13 11-17.5 Marital status 0.961 Married 277 (92.3) 15.1 (7.4) 13 11-18 Single/Widow/Dervoce 23 (7.7) 14.7 (7.1) 14 9-19 Occupation 0.0001 Stable income jobs 66 (22.0) 18.8 (9.2) 16.5 13-23 Unstable income jobs 163 (54.3) 13.5 (6.5) 13 10-16 No income 71 (23.7) 15.4 (6) 14 11-19 Economic status 0.0070 Poor 19 (6.3) 11.5 (6.0) 11 8-13 Near poor 24 (8.0) 13.1 (6.2) 12 11-15.5 Average 257 (85.7) 15.6 (7.4) 13 11-19 Health insurance benefits 0.5507 100% 153 (51.0) 15.4 (8.1) 13 11-19 95% 36 (12.0) 15.9 (6.6) 14 11.5-20.5 80% 111 (37.0) 14.4 (6.5) 13 11-17 Type of cancers 0.0252 Oesophagus cancer 39 (13.0) 12.3 (6.0) 12 8-15 Stomach cancer 15 (5.0) 13.3 (3.3) 13 13-16 Colorectal cancer 30 (10.0) 15.9 (7.2) 13 11-22 Liver cancer 32 (10.7) 15.4 (7.1) 15 10-18.5 Biliary/pancreatic cancer 112 (37.3) 16.6 (8.3) 14 11-21 Breast cancer 72 (24.0) 14.2 (6.8) 13 11-15 Stages of cancer 0.343 I 6 (2.0) 12.3 (2.8) 11.5 11-14 II 54 (18.0) 13.8 (7.8) 13 9-18 III 110 (36.7) 15.2 (7.1) 13 11-16 IV 130 (43.3) 15.7 (7.4) 13 11-20 Treatment modality 0.0385 Surgery 4 (1.3) 18.5 (17.4) 12.5 8.5-28.5 Surgery and chemotherapy 153 (51.0) 16.3 (8.0) 14 11-20 Chemotherapy 83 (27.7) 13.2 (5.8) 13 10-16 Radiotherapy 54 (18.0) 15 (6.3) 13 11-17 Palliative care 6 (2.0) 10.5 (4.0) 10.5 8-14 Alcohol use 0.670 Yes 175 (58.3) 14.9 (7.3) 13 11-17 No 125 (41.7) 15.4 (7.4) 13 11-19 Cigarette status 11-17 0.953 Yes 146 (48.7) 14.9 (6.8) 13 10-19 No 154 (51.3) 15.3 (7.8) 13 11-17 8. A linear regression should be performed to understand the contribution of independent variables to the COST score. Reply 8: We appreciate your suggestion once again. To address the skewed distribution of the COST score, we performed a multivariate quantile regression model to identify its predictors. We focused on the 50th percentile (median) of the COST score in this regression analysis. All results are presented in Table 4 and the results section (Page 15, line 196-197). Table 4. A multivariate quantile regression analysis for predictors of COST score. Factors Coefficient [95% CI] p-value Age group (≥ 60 vs. <60) 2.50 -0.12 to 5.12 0.062 Sex (Women vs. Men) -5.96 -10.39 to -1.54 0.008 Education level (From secondary school and above vs.Less than secondary school) 0.39 -2.46 to 3.24 0.786 Residence areas (Rural vs. Urban ) -4.57 -7.41 to 1.73 0.002 Religious (Yes vs. No) -1.50 -4.74 to 1.74 0.363 Marital status (Yes vs. No) 1.11 -3.44 to 5.65 0.632 Occupation (vs. Stable income jobs) Unstable income jobs -5.39 -8.71 to -2.07 0.002 No income -4.64 -8.63 to -0.65 0.023 Family economic status (vs. Poor) Near poor 0.82 -5.58 to 7.23 0.801 Average 2.96 -2.1 to 8.03 0.250 Health insurance copayment (vs. 100%) 95% -4.07 -8.35 to 0.2 0.062 80% -0.86 -3.49 to 1.78 0.522 Types of cancer (vs. Oesophagus cancer) Stomach cancer 1.29 -6.64 to 9.21 0.750 Colorectal cancer 2.68 -3.32 to 8.68 0.380 Liver cancer 3.00 -2.39 to 8.39 0.274 Biliary/pancreatic cancer 2.04 -2.77 to 6.84 0.405 Breast cancer 0.07 -5.66 to 5.8 0.980 Stages of cancer (vs. Stage I) II 4.18 -4.63 to 12.99 0.351 III 4.36 -4.19 to 12.91 0.317 IV 5.11 -3.52 to 13.74 0.245 Treatment modality (vs. Surgery) Surgery and chemotherapy 1.68 -8.87 to 12.23 0.754 Chemotherapy -0.25 -10.8 to 10.3 0.963 Radiotherapy 0.11 -10.85 to 11.06 0.985 Palliative care -5.54 -18.94 to 7.87 0.417 Alcohol use (No vs. Yes) 2.86 -0.64 to 6.36 0.109 Cigarette smoking status (No vs. Yes) 2.36 -0.98 to 5.69 0.165 CI, Confidence Interval Attachments Attachment Submitted filename: 2_1 response to reviewers.docx https://doi.org/10.1371/journal.pone.0306339.r004
17 Jun 2024 Decision Letter - Le An Pham, Editor Validation of the COmprehensive Score for Financial Toxicity (COST) in Vietnamese Patients with Cancer PONE-D-24-12510R2 Dear Dr. Tran, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager® and clicking the ‘Update My Information' link at the top of the page. If you have any questions relating to publication charges, please contact our Author Billing department directly at authorbilling@plos.org. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Le An Pham, Ph.D,MD Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: https://doi.org/10.1371/journal.pone.0306339.r005
Formally Accepted
19 Jun 2024 Acceptance Letter - Le An Pham, Editor PONE-D-24-12510R2 PLOS ONE Dear Dr. Tran, I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now being handed over to our production team. At this stage, our production department will prepare your paper for publication. This includes ensuring the following: * All references, tables, and figures are properly cited * All relevant supporting information is included in the manuscript submission, * There are no issues that prevent the paper from being properly typeset If revisions are needed, the production department will contact you directly to resolve them. If no revisions are needed, you will receive an email when the publication date has been set. At this time, we do not offer pre-publication proofs to authors during production of the accepted work. Please keep in mind that we are working through a large volume of accepted articles, so please give us a few weeks to review your paper and let you know the next and final steps. Lastly, if your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. If we can help with anything else, please email us at customercare@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Professor Le An Pham Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0306339.r006

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