PONE-D-21-19005

Screening for undiagnosed non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH): a population-based risk factor assessment using vibration controlled transient elastography (VCTE)

PLOS ONE

Dear Dr. Eskridge,

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Daisuke Tokuhara

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PLOS ONE

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Additional Editor Comments (if provided):

I deeply appreciate the authors' sincere efforts for the development of screening tool for NAFLD. Reviewer provided the constructive comments for the manuscript. I hope those comments will help authors to prepare for the revised manuscript.

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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: Partly

Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: No

Reviewer #2: Yes

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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: Yes

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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: Yes

Reviewer #2: Yes

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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 current manuscript describes a self-selected population based study to identify patients with liver steatosis and/or liver fibrosis with use of transient elastography (TE) combined with controlled attenuation parameter (CAP). The aim of the study was to identify participants with steatosis and cirrhosis or fibrosis attributable to NASH, with the ultimate goal to demonstrate that community based screening can raise awareness, increased uptake of screening and affect behavior changes in (asymptomatic) NAFLD/NASH patients. The study included 940 patients of which baseline characteristics, co-morbidity and lifestyle variables were collected, further all patients underwent TE with CAP measurements to classify whether patients have NAFLD (steatosis S3), NASH (Fibrosis F3-4) or no abnormalities. In total 57% of the participants had steatosis without fibrosis (NAFLD) while 16% of patients had both fibrosis and steatosis (NASH). Identified risk factors in this study correspond with risk factors identified in literature. This paper contains usefull data for clinical practice, however there are some issues that need to be addressed by the authors

Major comments

I have difficulties with the various categories and definitions used in this paper for different analyses, which makes interpretation confusing. For example Table 4 presents four categories of steatosis and stiffness where S1 steatosis and F1 fibrosis are used. Later NAFLD is defined as having steatosis S3 and NASH is defined as having fibrosis F3-4 (which is defined in as steatosis and fibrosis in the abstract) and it is unclear if the NAFLD patients have no or mild fibrosis and whether the NASH patients can also have no steatosis (F0)? Further the logistic regression analysis seems to be performed on S3 steatosis (NAFLD) and F3-4 fibrosis (NASH) however in the results is F1 described, so this is unclear as well. I would advise the authors to define NAFLD en NASH based on literature and based on both steatosis and fibrosis stages and then perform all analyses on these stages.

Furthermore the manuscript is moderately written, not conform the usual outline of a paper. For example some methods are described in the results, the statistical analyses section contains a paragraph about collecting co-morbidity and life style and no strengths and limitations are described in the discussion. Also the introduction is too long and not concise, try to make a logical story here.

Minor comments

Abstract

- The authors describe 3 different aims, please describe more clearly

- 38: 1070 participants is misleading as 940 participants were included

Introduction

- Please try to be more concise in the introduction, the introduction now is far too long in my opinion

- What is the knowledge gap, has this type of population based screening been done before and what are the results?

- The aim of the study or research questions should be clearly presented in the last paragraph of the introduction

Study overview

- The aim is community based screening however this study is performed in self-selected participants which has a high risk of bias, this should be mentioned in the manuscript

Methods

- Screening: If I understand correct the authors used transient elastography with controlled attenuation parameter (CAP), please describe this clearly

- The gold standard for detecting steatosis based on EASL guidelines is ultrasound, can the authors explain why ultrasound is not used and describe this in the manuscript?

- In reading the statistical analyses paragraph there are some questions that come to my mind such as: Did the authors correct for multiple testing? Why did the authors perform chi square and later logistic regression? Was it univariate of multivariate regression analysis?

- Why did the authors include around 1000 patients, was this calculated or was there a pre-defined time schedule?

Results

- The baseline characteristics table (table 3) does not contain all information, please add all the other collected variables such as alcohol consumption, co-morbidity, BMI to describe the population in more detail etcetera.

- 237: Patients were categorized, this is methods

- Table 4: in the methods only F3-4 are described as relevant and only S3. However in these categories also F1 is described as fibrosis while TE performes bad in this category. See the advice in major comments.

- What is the explanation for patients with stiffness without fat

- 268: clinically obese, how is this defined?

- Table 6: This table is not necessary as the odds ratios are described in table 7

- Table 7: please use NASH and NAFLD in the grey rows, or describe the degree of fibrosis and steatosis.

- 287: Here F1 is mentioned while I understood that the analyses were performed on participants with F3-4 fibrosis? How are the analyses done?

Discussion

- 371: Participants 40-49 year were at highest risk for what? NAFLD or NASH? Please describe more clear.

- 382 – 387 repetition of results, please be more concise and interpret the findings.

- Strenghts and limitations are missing

- 393: This study shows an association between diet and steatosis and fibrosis, however it does not show that it lowers the risk. Also, it can be questioned how precise this data is as both physical activity and diet can change from week to week.

Typo

- 39: ‘were’ should be removed

- 213: Crohn instead of Chron, ulcerative colitis instead of colitis

- Table 3: please change ‘blank’ into ‘missing’

Reviewer #2: I totally agreed with the proposal that high-risk individuals should be screened for NAFLD by means of VCTE even in the absence of symptoms and that community-based screenings by using VCTE are an effective tool.

Comment 1: Current study clearly demonstrated the usefulness of VCTE for the screening of NAFLD in adult population. A previous study (Cho Y, et al. Plos One. 2015. 10. e0137239) have also demonstrated the significance of VCTE in the assessment of NAFLD in pediatric patietns. I recommend to cite this previous paper that will further strengthen the significance of authors' proposal.

Comment 2: I have another comment should be addressed as a study limitaion in the revised manuscript. The most significant and difficult issue to be discussed is the cut off and/or reference value of CAP to determine NAFLD. Authors used the cut off value of CAP for determining the presence of NAFLD based on the previous study (Zhang X et al. Clin Mol Hepatol. 2020). However there are currently no established cut-off value of CAP of NAFLD. Numerous studies provided or used original cut off or reference value of CAP for NAFLD and healthy individuals in adult, children and adolescents. Therefore I strongly recommend to cite at least the following references from different countries in the revised manuscript. Then authors should add the study limitation in terms of the use of the cut off or reference value of CAP. For example, discrepancies of the cut off and/or reference value may relate to differences in the study desin and populations including disease aetiologies, the prevalence of obesity and extent of subcutaneous adiposity, and the severity of steatosis, which may influence CAP performance.

(Reference 1) Sasso M, et al. Ultrasound Med Biol. 2010;36(11):1825-35.

(Reference 2) de Lédinghen V, et al. Liver Int. 2012;32(6):911-8.

(Reference 3) Tokuhara D, et al. Plos ONE. 2016;11:e0166683

(Reference 4) Isoura Y, et al. Obes Res Clin Pract. 2020;14(5):473-478

(Reference 5) Chon YE, et al. Liver Int. 2014;34(1):102-9.

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Reviewer #1: No

Reviewer #2: No

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Screening for undiagnosed non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH): a population-based risk factor assessment using vibration controlled transient elastography (VCTE)

PONE-D-21-19005R1

Dear Dr. Eskridge,

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.

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Kind regards,

Daisuke Tokuhara

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

I deeply appreciate authors' efforts for addressing to the reviewers' comments. Revised manuscript is well constructed. Data are well supporting the results and discussion.

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: All comments have been addressed

Reviewer #3: All comments have been addressed

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2. 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 #2: Yes

Reviewer #3: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #2: Yes

Reviewer #3: Yes

**********

4. 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 #2: Yes

Reviewer #3: Yes

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5. 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 #2: Yes

Reviewer #3: Yes

**********

6. 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 #2: I deeply appreciate all of efforts of authors for revision.

The revised manuscript is well addressed to the reviewers' comments.

I have no further comments.

Reviewer #3: Revised manuscript appropriately addressed to the reviewers' comments. I have no further comments on the current version of the manuscript.

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7. 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 #2: No

Reviewer #3: No