Use of the Vitiligo Extent Score: a protocol for a scoping review

Abstract

Introduction

Vitiligo is a chronic skin condition with no cure. Clinical assessment and treatment evaluation relies heavily on clinometry tools and expert knowledge. The Vitiligo Extent Score has been proposed as one of the most reliable and easy-to-use clinometry tools for vitiligo.

Methods and analysis

We proposed a scoping review to identify all the available evidence on the clinical research availability around the Vitiligo Extent Score. The following databases will be searched: MEDLINE (PubMed), Embase, Open Grey, Lens and Directory of Open Access Journals. In addition, the approach proposed in the Joanna Briggs Institute Reviewer’s Manual will be followed. Finally, this review will be reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews.

Ethics and dissemination

Ethics approval for this review is not required. We intend to publish the results in a specialised peer-reviewed journal and local, national and international conference presentations. It will also be incorporated as educational material in our institution’s postgraduate programme in dermatology.

Correspondence to Dr Andrea Arango-Salgado; [email protected]

STRENGTHS AND LIMITATIONS OF THIS STUDY

• The proposed strategy includes an extensive search in grey literature databases and no language restrictions.

• The design with several research questions will allow for assessing the clinical evidence thoroughly.

• This scoping review will only evaluate one of the several available measurement instruments for vitiligo.

Introduction

Description of the condition

Vitiligo is a chronic, acquired, autoimmune pigmentary disorder that affects up to 2% of the population. No preference for race, ethnic group or sex has been found. The average age of presentation is between 10 and 30 years. However, more than 50% of patients develop the disease before age 20.^{1 2}

It is a multifactorial disorder, and several mechanisms have been proposed to be responsible for melanocyte destruction.³ Among the most important are genetics, autoimmune factors, response to oxidative stress, generation of inflammatory mediators and mechanisms of melanocyte detachment.⁴ Recently, vitiligo therapy has focused on modulating the inflammatory response mediated by releasing proinflammatory cytokines and neuropeptides that cause vascular dilation and the immune response. This mechanism could play a leading role in the pathogenesis of the disease.^{5 6}

Clinically, it is characterised by the presence of achromic, symmetrical and well-defined macules, which may be accompanied by pigment loss at the level of the hair follicle. The condition has also been classified according to its extension into segmental, non-segmental and mixed vitiligo, and according to its clinical activity, into stable or unstable vitiligo.⁵ Although it can affect any body area, it is usually asymptomatic and can sometimes be associated with pruritus.⁷

Vitiligo is a multiorgan disease⁸ associated with systemic diseases such as arterial hypertension, dyslipidaemia, type 2 diabetes mellitus⁹ and other autoimmune disorders such as autoimmune thyroid disease, type 1 diabetes mellitus and pernicious anaemia, among others.¹⁰ In addition, vitiligo has also been related to a substantial psychological burden that deteriorates the quality of life for those who suffer from it, making it a catastrophic disease. Currently, no curative treatments are available, so therapy aims to stabilise the condition, prevent recurrences and positively impact the quality of life.

Description of Vitiligo Extent Score

Different measurement instruments for vitiligo are based on clinician-reported outcomes, such as the Vitiligo European Task Force assessment, Vitiligo Area Scoring Index (VASI) and point counting. Others include patient-reported outcomes, the Skindex-29, Skindex-16, Skindex-Teen, Dermatology Life Quality Index, Patient Benefit Index and Pictorial Representation of Illness and Self Measure. Finally, there are two observer-reported outcomes used: the Digital Image Analysis System and the Image Analysis Technique.¹¹ However, a systematic review found that none of the instruments showed evidence of a good validation process or reliability.¹²

The Vitiligo Extent Score (VES) was developed in 2016 as a response to the shortcomings in validity, reliability and ease of use in the routine clinical practice of existing measurement instruments. Among the objectives at the time of development was a more precise measurement of the extent of the disease and the sensitivity to change that would evaluate the response to treatment and make different research results comparable.¹³

The clinical evaluation of conditions that imply an estimated affected area is a challenging scenario, and we need tools that minimise the variation introduced by the operator. One of the most widely used clinometry tools in vitiligo is the VASI, which estimates compromise using hand units. One hand unit, the palm plus the volar surface of all the digits, is approximately 1% of the total body surface area (BSA). One of the difficulties with this method is the overestimation of the BSA since one hand unit represents between 0.70% and 0.76% of the BSA.¹⁴ During the development and validation of the VES, this was compared with the VASI, finding a greater inter-rater and intrarater reliability that seemed to be accentuated in cases of more extensive vitiligo. The researchers also documented a shorter average time for the application of the VES and a higher score for the VES in the subjective assessment of user-friendliness, rapidity and feeling of reliability.¹³

The main strengths of the VES are its ease of use, which is quite intuitive, and the fact that the evaluation based on images diminishes the effect of the evaluator’s appreciation and greater consistency in the follow-up of the disease in the patients. Finally, its category-based reporting gives it an advantage compared with other tools.

Objectives

The main objective of the proposed scoping review is to identify the available evidence to provide an overview of the clinical research availability around the VES.

Why this review is important

The VES seems to be a clinometry tool for vitiligo that can be applied quickly in the usual care of patients. In its development phase, it showed outstanding reliability and sensitivity to change, essential when evaluating, for example, patient response to treatment.

A recent systematic review concludes that the VES is the most effective tool to assess affected BSA in people with vitiligo.¹¹ This is why it is vital to know the extent to which the VES has been adopted as a tool in clinical research, its operational characteristics outside the validation population and whether and what modifications have been proposed.

Methods

Scoping review

This is a protocol for a systematic scoping literature review on the extent of clinical research on VES as a clinical tool for outcome measures in vitiligo.

The scoping review method was selected because VES is a relatively new clinical scoring instrument. This methodology allows for different types of research to be summarised and to identify the gaps for further research.¹⁵ The scoping review will follow the approach proposed in the Joanna Briggs Institute Reviewer’s Manual.¹⁶ In addition, it will be reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR).¹⁷

The research questions

The main research question is: ‘What has been the extent of clinical research on VES as a clinical scoring instrument for measuring outcomes in vitiligo?’

The following are the research subquestions:

• What is the reported reliability of VES?

• What are VES’ smallest detectable change and the minimal important change?

• Has VES been used to measure vitiligo response to therapy?

• Has VES been compared with any other clinical scoring instruments?

• Does VES have any cross-cultural validation?

• Have any modifications been proposed to VES?

Inclusion criteria

We will include any study on clinical research using VES.

Exclusion criteria

Case reports and narrative reviews will not be considered in this review.

Search methods for identification of studies

Electronic searches

The following databases will be searched from inception to the specified date:

• MEDLINE (PubMed) until September 2022.

• Embase until September 2022.

Sources for identification of grey literature:

• Open Grey.

• Lens.

• Directory of Open Access Journals.

Studies in any language, from any country and on any date will be included.

Searching other resources

We will screen reference lists from relevant published studies, including trials, systematic reviews, meta-analyses and narrative reviews.

The review will begin in September 2022 and is planned to be completed between March and June 2023.

The proposed search strategy and terms are presented in online supplemental table 1.

Data collection and charting

Selection of studies

Following the search, all identified citations will be uploaded into EndNote V.20.4.1¹⁸ and duplicates will be removed. To determine the studies to be included, two authors (PAR-G, SO-J) will independently scan the title and abstract of every record retrieved in the search. All potentially relevant articles that answer any of the research questions will be read in full. If any differences or discussions arise, they will be resolved by a third author (AA-S) and justified in a group meeting with all the authors.

The selection process will follow the recommendations in the PRISMA-ScR checklist,¹⁷ and a PRISMA flow chart of study selection will be presented following the PRISMA statement.¹⁹

Data charting

Two authors will capture relevant information from each included study in a data charting form that contains the following fields: author(s), year of publication, country of origin, the aim of the study, study population and sample size, study design and key findings that relate to the scoping review questions. During this process, the data charting form will be reviewed in periodic meetings to ensure proper use and complete data capture.

Presentation of the results

A narrative report will be produced to summarise the extracted data around the following conceptual categories: reliability of VES, score change in VES, VES as a response to therapy tool, VES compared with other clinical scoring instruments, cross-cultural validation and VES modifications. The selection of conceptual categories will be conducted via an iterative process in which the categories may change after the review. Following the review, the authors will decide whether any tables or charts will help in the presentation of the results, grouping information regarding any relevant information field defined in the charting form or the conceptual categories.

Patient and public involvement

No patients were involved in developing this protocol, and no patients will be included in the review.

Discussion

This review aims to synthesise the evidence around using VES as a clinometry tool in vitiligo care. Evidence from development studies suggests that the VES overcomes some of the problems of other measurement instruments.

Following the initial development of any measurement instrument, the behaviour of its operating characteristics outside the development population must be assessed. This aspect is of fundamental importance in a tool that depends on assessing changes in the skin.

Finally, the instrument may have undergone changes that make it easier to apply or that allow its use in slightly different situations.

Ethics statements

Patient consent for publication

Not applicable.

Footnote

Contributors AA-S and CEB-M conceived and designed the review. CEB-M led the development of the search strategy. AA-S and CEB-M offered guidance during the design of the protocol. AA-S, CEB-M, PAR-G and SO-J contributed to subsequent revisions and approved the protocol prior to its submission.

Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

Competing interests None declared.

Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

Provenance and peer review Not commissioned; externally peer reviewed.

Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

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