Reliability assessment of the OMERACT whole-body magnetic resonance imaging scoring system for juvenile idiopathic arthritis.

Inter-reader reliability of a new scoring system for evaluating joint inflammation and enthesitis in whole body MRI (WBMRI) in juvenile idiopathic arthritis was tested. The scoring system grades 732 item-region combinations of bone marrow and soft tissue changes for commonly involved joints and entheseal sites. Five radiologists rated 17 WBMRI scans through an online rating platform. Item-wise reliability was calculated for 117 items with non-zero scores in >10 % of readings. Interquartile ranges of the five-reader Kappa reliability coefficients were 0.58-0.73 (range: 0.36-0.88) for the joints, 0.65-0.81 (range: 0.39-0.95) for the entheses, and 0.62-0.75 (range: 0.60-0.76) for chronic nonbacterial osteomyelitis-like lesions.

Embracing unity at OMERACT: Valuing equity, promoting diversity, fostering inclusivity.

OBJECTIVE: To increase awareness and understanding of the principles of Equity, Diversity, and Inclusivity (EDI) within Outcome Measures in Rheumatology's (OMERACT) members. For this, we aimed to obtain ideas on how to promote and foster these principles within the organization and determine the diversity of the current membership in order to focus future efforts. METHODS: We held a plenary workshop session at OMERACT 2023 with roundtable discussions on barriers and solutions to increased diversity within OMERACT. We conducted an anonymous, web-based survey of members to record characteristics including population group, gender identity, education level, age, and ability. RESULTS: The workshop generated ideas to increase diversity of participants across the themes of building relationships [12 topics], materials and methods [5 topics], and conference-specific [6 topics]. Four hundred and seven people responded to the survey (25 % response rate). The majority of respondents were White (75 %), female (61 %), university-educated (94 %), Christian (42 %), spoke English at home (60 %), aged 35 to 55 years (50 %), and did not report a disability (64 %). CONCLUSION: OMERACT is committed to improving its diversity. Next steps include strategic recruitment of members to the EDI working group, drafting an EDI mission statement centering equity and inclusivity in the organization, and developing guidance for the OMERACT Handbook to help all working groups create actionable plans for promoting EDI principles.

OMERACT validation of a deep learning algorithm for automated absolute quantification of knee joint effusion versus manual semi-quantitative assessment.

OBJECTIVE: To begin evaluating deep learning (DL)-automated quantification of knee joint effusion-synovitis via the OMERACT filter. METHODS: A DL algorithm previously trained on Osteoarthritis Initiative (OAI) knee MRI automatically quantified effusion volume in MRI of 53 OAI subjects, which were also scored semi-quantitatively via KIMRISS and MOAKS by 2-6 readers. RESULTS: DL-measured knee effusion correlated significantly with experts' assessments (Kendall's tau 0.34-0.43) CONCLUSION: The close correlation of automated DL knee joint effusion quantification to KIMRISS manual semi-quantitative scoring demonstrated its criterion validity. Further assessments of discrimination and truth vs. clinical outcomes are still needed to fully satisfy OMERACT filter requirements.

Standardization of interstitial lung disease assessment by ultrasound: results from a Delphi process and web-reliability exercise by the OMERACT ultrasound working group.

OBJECTIVES: Over the last years ultrasound has shown to be an important tool for evaluating lung involvement, including interstitial lung disease (ILD) a potentially severe systemic involvement in many rheumatic and musculoskeletal diseases (RMD). Despite the potential sensitivity of the technique the actual use is hampered by the lack of consensual definitions of elementary lesions to be assessed and of the scanning protocol to apply. Within the Outcome Measures in Rheumatology (OMERACT) Ultrasound Working Group we aimed at developing consensus-based definitions for ultrasound detected ILD findings in RMDs and assessing their reliability in dynamic images. METHODS: Based on the results from a systematic literature review, several findings were identified for defining the presence of ILD by ultrasound (i.e., Am-lines, B-lines, pleural cysts and pleural line irregularity). Therefore, a Delphi survey was conducted among 23 experts in sonography to agree on which findings should be included and on their definitions. Subsequently, a web-reliability exercise was performed to test the reliability of the agreed definitions on video-clips, by using kappa statistics. RESULTS: After three rounds of Delphi an agreement >75 % was obtained to include and define B-lines and pleural line irregularity as elementary lesions to assess. The reliability in the web-based exercise, consisting of 80 video-clips (30 for pleural line irregularity, 50 for B-lines), showed moderate inter-reader reliability for both B-lines (kappa = 0.51) and pleural line irregularity (kappa = 0.58), while intra-reader reliability was good for both B-lines (kappa = 0.72) and pleural line irregularity (kappa = 0.75). CONCLUSION: Consensus-based ultrasound definitions for B-lines and pleural line irregularity were obtained, with moderate to good reliability to detect these lesions using video-clips. The next step will be testing the reliability in patients with ILD linked to RMDs and to propose a consensual and standardized protocol to scan such patients.

Validation studies of rheumatoid arthritis patient-reported outcome measures in populations at risk for inequity: A systematic review and analysis using the OMERACT summary of measurement properties equity table.

BACKGROUND: Existing patient-reported outcome measures (PROMs) in rheumatoid arthritis (RA) may be limited in their applicability to populations that are at risk for inequities. We conducted a systematic review to identify and rate evidence in the validation studies for PROMs in populations at risk for inequity. METHODS: A systematic review of MEDLINE and EMBASE was completed. The search strategy was developed to identify measurement property studies for PROMs of interest (selected pain, disease activity, global evaluation and quality of life scales) in patients with RA. We identified experimental, observational, and qualitative studies reporting analysis of feasibility, construct validity and discriminant ability metrics for populations at risk for inequity by various factors including race, ethnicity, culture or language; employment status; sex and gender identity; education level; socioeconomic status; social support; age; health literacy and disability. These were rated based on the OMERACT Summary of Measurement Properties Equity table. RESULTS: From 19,786 titles and abstracts screened, we identified 14 unique studies reporting validation metrics for pain (n = 3), DAS28-ESR or DAS28-CRP (n = 2), ACR20 (n = 1), patient global assessment (n = 2), EQ5D (n = 4), and PROMIS® (n = 3) by race (n = 10 studies), age (n = 6 studies), sex (n = 5 studies), education level (n = 2 studies), and disability, literacy, employment status, social support level and socioeconomic status (n = 1 study each). Five studies reported on feasibility, 12 reported construct validity metrics, and 4 studies reported on discriminant validity metrics. All studies by culture or language were rated as having good measurement property metrics. There was limited assessment of measurement property metrics for other populations at risk for inequity. CONCLUSION: Our study highlights important gaps in patient representation in rheumatology research for accepted outcome measures. New outcome measures being developed for research purposes and clinical practice should ensure and report representation of patients from populations at risk for inequities in the testing of metrics of feasibility, construct validity and discriminant ability metrics.

Retrospective longitudinal assessment of ultrasound gout lesions using the OMERACT semi-quantitative scoring system.

OBJECTIVES: The objectives of this study were (i) to evaluate the responsiveness of gout-specific US lesions representing urate deposition in patients receiving treat-to-target urate-lowering therapy using a binary and the OMERACT-defined semi-quantitative scoring systems; (ii) to determine the most responsive US measure for urate deposition and the optimal joint/tendon set for monitoring this. METHODS: US (28 joints, 14 tendons) was performed in microscopically verified gout patients initiating/increasing urate-lowering therapy and repeated after 6 and 12 months. Static images/videos of pathologies were stored and scored binarily and semi-quantitatively for tophus, double contour sign (DC) and aggregates. Lesion scores were calculated at patient level, as were combined crystal sum scores. Responsiveness of lesions-scored binarily and semi-quantitatively-was calculated at both patient and joint/tendon levels. RESULTS: Sixty-three patients underwent longitudinal evaluation. The static images/videos assessed retrospectively showed statistically significant decreases in tophus and DC, when scored binarily and semi-quantitatively, whereas aggregates were almost unchanged during follow-up. The responsiveness of the semi-quantitative tophus and DC sum scores were markedly higher than when using binary scoring. The most responsive measure for urate deposition was a combined semi-quantitative tophus-DC-sum score. A feasible joint/tendon set for monitoring included knee and first-second MTP joints and peroneus and distal patella tendons (all bilateral), representing the most prevalent and responsive sites. CONCLUSION: The OMERACT consensus-based semi-quantitative US gout scoring system showed longitudinal validity with both tophus and DC being highly responsive to treatment when assessed in static images/videos. A responsive US measure for urate deposition and a feasible joint/tendon set for monitoring were proposed and may prove valuable in future longitudinal studies.

Prologue: 2021 Annual Meeting of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA).

The Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) held its annual meeting in 2021 in an online format due to travel restrictions during the ongoing COVID-19 (coronavirus disease 2019) pandemic. The virtual meeting was attended by rheumatologists, dermatologists, representatives of biopharmaceutical companies, and patient research partners. Similar to previous years, GRAPPA's annual meeting focused on the 3 overlapping missions of education, research, and clinical care of psoriatic disease (PsD). The virtual meeting allowed a variety of different types of sessions to be held, including the trainee symposium, keynote lectures, interactive sessions (5 Meet the Experts sessions, a debate on first-line therapy, and 5 guided poster sessions), 4 workshops (trainee workshop focusing on the diagnosis of PsD, ultrasound, magnetic resonance imaging, and the International Dermatology Outcome Measures group), updates on a variety of research topics (research findings from the 2020 GRAPPA research grant awardees, 3 basic science talks, Outcome Measures in Rheumatology [OMERACT] Working Group efforts, and Collaborative Research Network progress), current "hot topics" (use of Janus kinase inhibitors, promoting diversity and inclusion in PsD, progress on the updated GRAPPA treatment recommendations, and the introduction of the Young GRAPPA member group), and the presentation of four 2021 GRAPPA grant awardees and election results. In this prologue, we introduce the papers that summarize this meeting.

Development of an extension of the OMERACT Summary of Measurement Properties table to capture equity considerations: SOMP-Equity.

OBJECTIVE: To develop an equity extension of the OMERACT Summary of Measurement Properties (SOMP) Table, SOMP Equity to describe whether a patient reported outcome measure (PROM) works well among patients of diverse languages and cultures, education levels, and other population characteristics. METHODS: We used the PROGRESS-Plus framework to categorize equity characteristics assessed in trials of PROM. PROGRESS refers to Place of residence, Race/ethnicity/culture/language, Occupation, Gender/sex, Religion, Education, Socioeconomic status, and Social Capital, while the 'plus' captures additional characteristics, such as age. We pilot tested our SOMP Equity Extension using the Health Assessment Questionnaire (HAQ) as a prototypical PROM. RESULTS: The SOMP Equity Extension retains the same columns as the original OMERACT SOMP (domain match, feasibility, construct validity, test-retest reliability, longitudinal construct validity, clinical trial discrimination, thresholds of meaning) but uses the PROGRESS-Plus characteristics as rows. We found several examples of studies of the HAQ which had assessed one or more PROGRESS-Plus characteristics. CONCLUSIONS: The most commonly reported equity considerations were related to language. OMERACT Equity virtual meeting participants were polled and they indicated that the SOMP Equity Extension is useful for highlighting and tracking equity considerations for OMERACT Core Outcome Measurement Instruments.

Improving benefit-harm assessment of glucocorticoid therapy incorporating the patient perspective: The OMERACT glucocorticoid core domain set.

OBJECTIVE: Our primary objective was to develop an Outcome Measures in Rheumatology (OMERACT) core domain set to capture the impact of glucocorticoids (GC), both positive and negative, on patients with Rheumatic conditions. METHODS: The OMERACT Filter 2.1 was used to guide core domain selection. Systematic literature reviews, qualitative studies and quantitative surveys were conducted by the OMERACT GC Impact working group to identify candidate domains for a core domain set. A summary of prior work and Delphi exercise were presented at the OMERACT 2020 virtual GC workshop. A proposed GC Impact core domain set derived from this work was presented for discussion in facilitated breakout groups. Participants voted on the proposed GC Impact core domain set. RESULTS: 113 people, including 23 patient research partners, participated in two virtual workshops conducted at different times on the same day. The proposed mandatory domains to be evaluated in clinical trials involving GCs were: infection, bone fragility, hypertension, diabetes, weight, fatigue, mood disturbance and death. In addition, collection of disease specific outcomes was included in the core domain set as "mandatory in specific circumstances". The proposed core domain set was endorsed by 100% (23/23) of the patient research partners and 92% (83/90) of the remaining participants, including clinicians, researchers and industry stakeholders. CONCLUSION: A GC Impact core domain set was endorsed at the OMERACT 2020 virtual workshop. The OMERACT GC Impact working group will now progress to identify, develop and validate measurement tools to best address these domains in clinical trials.

Patient preferences to value health outcomes in rheumatology clinical trials: Report from the OMERACT special interest group✰.

OBJECTIVE: To inform a research plan for future studies by obtaining stakeholder input on the application of preference-based methods to clinical trial design. METHODS: We conducted a virtual OMERACT session to encourage stakeholder engagement. We developed materials for the session to facilitate discussion based on identified case examples and feedback sessions. RESULTS: Participants prioritized incorporating patient preferences in all aspects of trial design with an emphasis on outcome selection. Participants highlighted the need for careful consideration around preference heterogeneity and equity factors. CONCLUSION: Including patient preferences in trial design was considered a priority requiring further exploration to develop comprehensive guidance.

OMERACT definition and reliability assessment of chronic ultrasound lesions of the axillary artery in giant cell arteritis.

OBJECTIVES: To define chronic ultrasound lesions of the axillary artery (AA) in long-standing giant cell arteritis (GCA) and to evaluate the reliability of the new ultrasound definition in a web-based exercise. METHODS: A structured Delphi, involving an expert panel of the Large Vessel Vasculitis subgroup of the Outcome Measures in Rheumatology (OMERACT) Ultrasound Working Group was carried out. The reliability of the new definition was tested in a 2-round web-based exercise involving 23 experts and using 50 still images each from AA of long-standing and acute GCA patients, as well as 50 images from healthy individuals. RESULTS: The final OMERACT ultrasound definition of chronic changes was based on measurement and appearance of the intima-media complex. The overall reliability of the new definition for chronic ultrasound changes in longstanding GCA of the AA was good to excellent with Light's kappa values of 0.79-0.80 for inter-reader reliability and mean Light's-kappa of 0.88 for intra-reader reliability. The mean inter-rater and intra-rater agreements were 86-87% and 92%, respectively. Good reliabilities were observed comparing the vessels with longstanding versus acute GCA with a mean agreement and kappa values of 81% and 0.63, respectively. CONCLUSION: The new OMERACT ultrasound definition for chronic vasculitis of the AA in GCA revealed a good to excellent inter- and intra-reader reliability in a web-based exercise of experts.

Prologue: 2020 Annual Meeting of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA).

The Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) held its annual meeting in 2020 in an online format due to travel restrictions during the coronavirus disease 2019 (COVID-19; caused by SARS-CoV-2) pandemic. The virtual meeting was attended by 351 rheumatologists, dermatologists, representatives of biopharmaceutical companies, and patient research partners. Similar to previous years, GRAPPA's annual meeting focused on the 3 overlapping missions of education, research, and clinical care of psoriatic disease. Trainee sessions this year included the annual trainee symposium and a grant-writing workshop. Plenary sessions included updates on COVID-19 and psoriatic disease from multispecialty and patient perspectives, and updates on pustular psoriasis and associated musculoskeletal manifestations. Progress on research and updates were presented for the following groups: Collaborative Research Network, Outcome Measures in Rheumatology (OMERACT) Psoriatic Arthritis Working Group, International Dermatology Outcome Measures, Composite Measures, Education Committee, and Treatment Guidelines. New this year were 3 concurrent workshops on ultrasound assessment of joints and entheses, magnetic resonance imaging of psoriatic arthritis, and pustular psoriasis efficacy endpoints; 6 "Meet the Expert" sessions; and facilitated "poster tours." In our prologue, we introduce the papers that summarize this meeting.

Prologue: 2019 Annual Meeting of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA).

The 2019 Annual Meeting of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) was held in Paris, France, and was attended by rheumatologists, dermatologists, representatives of biopharmaceutical companies, and patients. As in previous years, GRAPPA members held a symposium for trainees to discuss their research in psoriatic disease with experts in the field. Other subjects featured during the annual meeting included a composites workshop to review continuous composite measures; the GRAPPA-Collaborative Research Network's third annual meeting; the need for a precision medicine approach to the treatment of psoriatic disease; updates from working groups in International Dermatology Outcome Measures and Outcome Measures in Rheumatology; a debate on the effectiveness of methotrexate in the treatment of psoriatic arthritis (PsA); updating recommendations for optimal treatment approaches for patients with PsA; an update on GRAPPA's research and educational projects; and the GRAPPA ultrasound (US) working group's goal to optimize the evaluation of enthesitis in patients with PsA using US through the development of a diagnostic US enthesitis tool. In this Prologue, we introduce the papers that summarize that meeting.

Prologue: 2018 Annual Meeting of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA).

The 2018 Annual Meeting of the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) was held in Toronto, Ontario, Canada, and was attended by rheumatologists, dermatologists, and representatives of biopharmaceutical companies and patients. As in previous years, GRAPPA members held a symposium for trainees to discuss their research in psoriatic disease with experts in the field. Other subjects featured during the annual meeting included GRAPPA-Collaborative Research Network's second annual meeting; the association between psoriatic disease and cardiovascular events; updates from working groups in International Dermatology Outcome Measures (IDEOM) and Outcome Measures in Rheumatology (OMERACT); a 2016 study that benchmarked care in psoriatic arthritis (PsA); the genetic contribution to PsA and strong need for genome-wide association studies on patients with PsA; the GRAPPA Ultrasound Working Group's goal to optimize the evaluation of enthesitis in patients with PsA using ultrasound through the development and validation of new instruments; and an update on GRAPPA's research and educational projects. In this prologue, we introduce the papers that summarize the meeting.

Video clip assessment of a salivary gland ultrasound scoring system in Sjögren's syndrome using consensual definitions: an OMERACT ultrasound working group reliability exercise.

OBJECTIVE: To develop ultrasound (US) definitions and a US novel scoring system for major salivary gland (SG) lesions in patients with primary Sjögren's syndrome (pSS) and to test their intrareader and inter-reader reliability using US video clips. METHODS: Twenty-five rheumatologists were subjected to a three-round, web-based Delphi process in order to agree on (1) definitions and scanning procedure of salivary gland ultrasonography (SGUS): parotid, submandibular and sublingual glands (PG, SMG and SLG); (2) definitions for the elementary SGUS lesions in patients with Sjögren's syndrome; (3) scoring system for grading changes. The experts rated the statements on a 1-5 Likert scale. In the second step, SGUS video clips of patients with pSS and non-pSS sicca cases were collected containing various spectrums of disease severity followed by an intrareader and inter-reader reliability exercise. Each video clip was evaluated according to the agreed definitions. RESULTS: Consensual definitions were developed after three Delphi rounds. Among the three selected SGs, US assessment of PGs and SMGs was agreed on. Agreement was reached to score only greyscale lesions and to focus on anechoic/hypoechoic foci in a semiquantitative matter or, if not possible on a qualitatively (present/absent) evaluation of fatty or fibrous lesions. Intrareader reliability for detecting and scoring these lesions was excellent (Cohen's kappa 0.81) and inter-reader reliability was good (Light's kappa 0.66). CONCLUSION: New definitions for developing a novel semiquantitative US score in patients with pSS were developed and tested on video clips. Inter-reader and intrareader reliabilities were good and excellent, respectively.

OMERACT Hip Inflammation Magnetic Resonance Imaging Scoring System (HIMRISS) Assessment in Longitudinal Study.

OBJECTIVE: To assess reliability, feasibility, and responsiveness of Hip Inflammation Magnetic resonance imaging Scoring System (HIMRISS) for bone marrow lesions (BML) in hip osteoarthritis (OA). METHODS: HIMRISS was scored by 8 readers in 360 hips of 90 patients imaged pre/post-hip steroid injection. Pre-scoring, new readers trained online to achieve intraclass correlation coefficient (ICC) > 0.80 versus experts. RESULTS: HIMRISS reliability was excellent for BML status (ICC 0.83-0.92). Despite small changes post-injection, reliability of BML change scores was high in femur (0.76-0.81) and moderate in acetabulum (0.42-0.56). CONCLUSION: HIMRISS should be a priority for further assessment of hip BML in OA, and evaluated for use in other arthropathies.

OMERACT Filter 2.1: Elaboration of the Conceptual Framework for Outcome Measurement in Health Intervention Studies.

OBJECTIVE: The Outcome Measures in Rheumatology (OMERACT) Filter 2.0 framework was developed in 2014 to aid core outcome set development by describing the full universe of "measurable aspects of health conditions" from which core domains can be selected. This paper provides elaborations and updated concepts (OMERACT Filter 2.1). METHODS: At OMERACT 2018, we discussed challenges in the framework application caused by unclear or ambiguous wording and terms and incompletely developed concepts. RESULTS: The updated OMERACT Filter 2.1 framework makes benefits and harms explicit, clarifies concepts, and improves naming of various terms. CONCLUSION: We expect that the Filter 2.1 framework will improve the process of core set development.

Improving Benefit-harm Assessment of Therapies from the Patient Perspective: OMERACT Premeeting Toward Consensus on Core Sets for Randomized Controlled Trials.

OBJECTIVE: Outcome Measures in Rheumatology (OMERACT) convened a premeeting in 2018 to bring together patients, regulators, researchers, clinicians, and consumers to build upon previous OMERACT drug safety work, with patients fully engaged throughout all phases. METHODS: Day 1 included a brief introduction to the history of OMERACT and methodology, and an overview of current efforts within and outside OMERACT to identify patient-reported medication safety concerns. On Day 2, two working groups presented results; after each, breakout groups were assembled to discuss findings. RESULTS: Five themes pertaining to drug safety measurement emerged. CONCLUSION: Current approaches have failed to include data from the patient's perspective. A better understanding of how individuals with rheumatic diseases view potential benefits and harms of therapies is essential.

Assessment of osteoarthritic features in the thumb base with the newly developed OMERACT magnetic resonance imaging scoring system is a valid addition to standard radiography.

OBJECTIVE: To investigate the construct validity of the new thumb base OA magnetic resonance imaging (MRI) scoring system (TOMS) by comparing TOMS scores with radiographic scores in patients with primary hand OA. DESIGN: In 200 patients (83.5% women, mean (SD) age 61.0 (8.4) years), postero-anterior radiographs and MR scans (1.5 T) of the right first carpometacarpal (CMC-1) and scaphotrapeziotrapezoid (STT) joints, were scored using the OARSI atlas and TOMS, respectively. The distributions of the TOMS scores (specified in results section) were stratified for the OARSI scores of corresponding radiographic features and investigated using boxplots and non-parametric tests. Furthermore, Spearman's rank or Phi correlation coefficients (ρ/φ) were calculated. RESULTS: For all features, especially for erosions and osteophytes, the prevalence found with MRI was higher than with radiography. TOMS osteophyte and cartilage loss scores differed statistically significant between corresponding OARSI scores in CMC-1 (0 vs 1; 1 vs 2). TOMS scores were positively correlated with radiographic scores in CMC-1 for osteophytes (coefficient [95% confidence interval], ρ = 0.75 [0.69; 0.81]), cartilage loss/joint space narrowing (ρ = 0.70 [0.62; 0.76]), subchondral bone defects (SBDs)/erosion-cyst (ρ = 0.41 [0.29; 0.52]), bone marrow lesions (BMLs)/subchondral sclerosis (ρ = 0.65 [0.56; 0.73]) and subluxation (φ = 0.65 [0.57; 0.73]); and in STT for osteophytes (ρ = 0.30 [0.17; 0.42]) and cartilage loss/joint space narrowing (ρ = 0.53 [0.42; 0.62]). CONCLUSIONS: In patients with hand OA, TOMS scores positively correlated with radiographic scores, indicating good construct validity. However, the prevalence of features on MR images was higher compared to radiographs, suggesting that TOMS might be more sensitive than radiography. The clinical meaning of these extra MR detected cases is currently still unknown.

Assessment of skin involvement in systemic sclerosis.

Skin involvement in SSc is an important marker of disease activity, severity and prognosis, making the assessment of skin a key issue in SSc clinical research. We reviewed the published data assessing skin involvement in clinical trials and summarized the major conclusions important in SSc clinical research. A systematic literature review identified randomized controlled trials using skin outcomes in SSc. Analysis examined the validity of the different skin measures based on literature findings. Twenty-two randomized controlled trials were found. The average study duration was 10.2 (s.d. 4.5) months, mean (s.d.) sample size 32.4 (32.6) and 26.7 (27.8) in intervention and control arms, respectively. The 17-site modified Rodnan skin score is a fully validated primary outcome measure in diffuse cutaneous SSc. Skin histology seems to be an appropriate method for evaluation of skin thickness. These findings have important implications for clinical trial design targeting skin involvement in SSc.