Development and validation of a patient-reported outcome measure for systemic sclerosis: the EULAR Systemic Sclerosis Impact of Disease (ScleroID) questionnaire

A study of the reliability and construct validity of the 1-minute sit-to-stand test for individuals with systemic sclerosis

OBJECTIVE

This study seeks to assess the reliability and construct validity of the 1-minute sit-to-stand test as an efficient tool for evaluating the functional capacity of individuals with systemic sclerosis, considering its time and space effectiveness.

METHODS

This cross-sectional study recruited forty-nine individuals with systemic sclerosis from a university hospital in Denmark. The 1-minute sit-to-stand test was conducted twice on the same day, with an interval of approximately 10 to 15 minutes between administrations, followed by a single administration of the 6-minute walk test. Reliability and validity were estimated using Bland-Altman statistics, intraclass correlation coefficient (ICC2,1), paired t-test, and Spearman's rank correlation coefficient (ρ).

RESULTS

The 1-minute sit-to-stand test exhibited excellent test-retest reliability with an ICC2,1 (CI) of 0.97 (0.95-0.99). The minimal metrically detectable change between separate measures on a subject for the difference in the measures to be considered real at the 95% confidence level was 2.9 repetitions and 11%, respectively. A learning effect of one repetition was observed between repeated measures. High construct validity was observed between the 1-minute sit-to-stand and 6-minute walk test (ρ = 0.78, p < .001).

CONCLUSIONS

This study demonstrates the 1-minute sit-to-stand test as highly reliable, with an 11% change indicating a true outcome change. It also demonstrates robust construct validity compared to the 6-minute walk test. The 1-minute sit-to-stand test appears feasible for assessing functional capacity in well-functioning individuals with systemic sclerosis, but prior familiarization with the task is recommended, as a small learning effect was observed with one repetition.

Disease Safety, Immunogenicity, and Efficacy of Recombinant Herpes Zoster Vaccine (RZV or Shingrix) in Autoimmune Rheumatic Diseases: Launching a Randomized Phase 4 Study

BACKGROUND

Patients with autoimmune rheumatic diseases (ARDs) are at an increased risk for herpes zoster (HZ). Vaccination is recommended for this population.

OBJECTIVE

The aim of this study was to evaluate the safety of vaccination with the recombinant zoster vaccine (Shingrix) in ARD patients, humoral immunogenicity (HI), cellular immunogenicity (CI), and the incidence of HZ.

METHODS

This randomized, double-blind, placebo-controlled phase 4 study involves 1180 ARD patients and a control group (CG) of 393 balanced healthy individuals, aged ≥50 years. ARD patients will be randomly assigned in a blinded manner (1:1 ratio) to 2 groups: vaccine or placebo (on days 0 and 42), administered intramuscularly. Outcomes will be assessed at baseline, 6 weeks, and 12 weeks after vaccination, including disease activity (using specific disease activity scores), HI, and CI. Adverse events will be assessed using a standardized questionnaire after each vaccine dose. Incident HZ cases will be monitored throughout the study. One year following the second dose, the persistence of HI and CI will be evaluated in both ARD patients and CG. HI and CI will be assessed using serum concentrations of anti-gE antibodies and the frequencies of gE-specific CD4+ T cells, respectively. Comparisons of anti-gE titers between ARD patients and CG at different time points will be analyzed using 2-way repeated-measures analysis of variance. Multiple regression analysis will be conducted, with a positive immune response as the dependent variable, and variables with p < 0.2 from univariate analysis as independent variables.

CONCLUSIONS

This large trial addresses a critical gap by examining disease safety, efficacy, adverse effects, and immunogenicity, considering the impact of diverse therapies following recombinant zoster vaccine administration in ARD patients.

Arthritis in patients with very early systemic sclerosis: a comprehensive clinical and prognostic analysis

OBJECTIVE

Arthritis is associated with a worse prognosis in established SSc. However, knowledge about its relevance in very early SSc (veSSc) is scarce. We aimed to assess the prevalence and phenotype of arthritis, as well as its prognostic impact, in patients with veSSc.

METHODS

We analysed patients with veSSc, defined as presence of Raynaud's phenomenon (RP) and/or at least one of: puffy fingers, antinuclear antibodies (ANA), abnormal capillaroscopy, not fulfilling the ACR/EULAR classification criteria for SSc at baseline. We investigated associations between arthritis and clinical parameters, followed by a longitudinal analysis to investigate arthritis as a potential predictor of progression towards established SSc.

RESULTS

We included 159 patients, of whom 108 had at least one follow-up visit. SSc-related arthritis occurred in 22/159 (13.8%) patients at baseline. Arthritis was mostly seronegative, symmetrical, oligo- or polyarticular, non-erosive, and rarely associated with elevation of inflammatory markers. More than half of the patients needed treatment with DMARDs. Anti-centromere antibodies (ACA) were negatively associated with arthritis (odds ratio 0.707, 95% CI 0.513-0.973, P = 0.033). Overall, 43/108 (39.8%) patients with follow-up progressed to established SSc during the observation time. Arthritis was not a significant predictor for progression to established SSc in a multivariable Cox regression.

CONCLUSION

In this first comprehensive analysis, we found a similar prevalence of arthritis in veSSc as seen in established SSc. Moreover, the use of DMARDs indirectly suggests a relevant disease burden.

The effect of tocilizumab treatment for skin fibrosis by inhibiting CD38+ macrophages in systemic sclerosis

BACKGROUND

Dermal and pulmonary fibrosis are the main clinical symptoms of systemic scleroderma (SSc), for which there are no effective therapeutic agents. Tocilizumab is thought to improve the symptoms of fibrosis, but the effect of tocilizumab on dermal fibrosis has not been explored. This study aims to investigate the therapeutic effect of tocilizumab on skin fibrosis by inhibiting CD38+ macrophages in the bleomycin-induced SSc mice model.

METHODS

The 8-week-old BALB/c mice were randomly divided into three groups: control group (PBS group), model group (BLM group), and tocilizumab group (TCZ group). The mRNA expression of VIMENTIN, TIMP1, and COL1A1 was measured by qPCR. Western blot was used to detect the protein expression of α-SMA, TGF-β, and COL1A1 in skin tissues. The expression of CD38+ macrophages in the BLM-induced fibrosis mouse model was verified by flow cytometry and immunofluorescence.

RESULTS

In comparison to the PBS control group, mice in the BLM group showed skin fibrosis, edema, thickness, and collagen deposition. The percentage of macrophages in the skin, peripheral blood, and spleen was significantly increased in the BLM group, and the percentage of CD38+ macrophages increased in the skin and peripheral blood but decreased in the spleen. After co-cultured with macrophages, L929 fibroblasts differentiated into myofibroblasts, with increased mRNA expression of COL1A1, COL3A, TGF-β, and Fibronectin. Furthermore, after being stimulated by LPS, RAW264.7 cells showed increased expression of IL-6 and CD38. The mRNA levels of COL1A1, COL1A2, COL3A, TGF-β, and Fibronectin in L929 fibroblasts were markedly increased when co-cultured with LPS-stimulated RAW264.7 cells. Tocilizumab treatment reduced dermal thickness and collagen deposition induced by BLM. Furthermore, the percentage of total macrophages and CD38+ macrophages in the skin and peripheral blood significantly decreased after tocilizumab treatment.

CONCLUSION

This study revealed that tocilizumab improved skin fibrosis in the SSc mice model, which was mediated by inhibiting skin and peripheral CD38+ macrophages.

EULAR recommendations for the treatment of systemic sclerosis: 2023 update

OBJECTIVES

To update the 2017 European Alliance of Associations for Rheumatology (EULAR) recommendations for treatment of systemic sclerosis (SSc), incorporating new evidence and therapies.

METHODS

An international task force was convened in line with EULAR standard operating procedures. A nominal group technique exercise was performed in two rounds to define questions underpinning a subsequent systematic literature review. The evidence derived was discussed and overarching principles, recommendations and future research agenda were iteratively developed with voting rounds.

RESULTS

The task force agreed on 22 recommendations covering 8 clinical/organ domains including Raynaud's phenomenon, digital ulcers, pulmonary arterial hypertension, scleroderma renal crisis, skin fibrosis, interstitial lung disease (ILD), gastrointestinal manifestations and arthritis. Most new recommendations are related to skin fibrosis and ILD. These included novel recommendations for the use of mycophenolate mofetil, nintedanib, rituximab and tocilizumab for the treatment of these crucial disease manifestations. The recommendations also included first-line and second-line interventions, providing increased utility for rheumatology practitioners. Important additions to the future research agenda included consideration of novel interventions for the management of vascular, musculoskeletal and gastrointestinal manifestations and calcinosis, as well as for the local management of digital ulcers.

CONCLUSION

These updated recommendations include the first set of synthetic and biological targeted therapies recommended for key fibrotic manifestations of SSc as well as first-line combination treatment for newly diagnosed pulmonary artery hypertension and prioritise a new research agenda for the coming years.

Performance of the EULAR Systemic sclerosis Impact of Disease (ScleroID) questionnaire as a patient-reported outcome measure for patients with diffuse systemic sclerosis

OBJECTIVE

Systemic sclerosis Impact of Disease (ScleroID) is the first comprehensive patient-reported outcome measure (PROM) specifically developed for systemic sclerosis (SSc). We investigated the performance of ScleroID in patients with diffuse cutaneous SSc (dcSSc), as a prerequisite for its use in randomised controlled trials (RCTs) testing potentially disease-modifying drugs.

METHODS

All patients with dcSSc from the large, multicentric, ScleroID cohort were included. SSc-Health Assessment Questionnaire (HAQ), EuroQol-5 Dimensions and 36-item Short Form Health Survey (SF-36) were used as comparators. The study includes a longitudinal arm with a reliability visit at 7±3 days and a 12 months follow-up visit. The performance of ScleroID in dcSSc was assessed according to the Outcome Measures in Rheumatology filter.

RESULTS

In total, 152 dcSSc patients were analysed (29% male, median age 54 years). ScleroID reflected well the disease impact of dcSSc, showing a good construct validity with high Spearman's correlation coefficients with comparators (SSc-HAQ, 0.79, 95% CI (0.69, 0.86); HAQ-Disability Index, 0.72 95% CI (0.60, 0.80); SF-36 physical score, -0.69 95% CI (-0.77, -0.60)). The internal consistency was strong (Cronbach's alpha 0.87, split-half reliability coefficient 0.88).In the longitudinal arm, 44 patients had a reliability visit and 113 had a follow-up visit, of whom 19/113 (17%) reported a significant change (11 improved, 8 worsened). ScleroID showed a good consistency and discriminative ability with excellent test-retest reliability (intraclass correlation coefficient 0.89, 95% CI (0.84, 0.92)) and moderate sensitivity to change (standardised response mean -0.63 in the improved subgroup and 0.48 in the worsened subgroup), but superior to the comparators.

CONCLUSION

The European Alliance of Associations for Rheumatology (EULAR) ScleroID performs well for patients with dcSSc. This supports its inclusion and regular assessment as PROM in RCTs.

Can we define difficult-to-treat systemic sclerosis?

INTRODUCTION

Systemic sclerosis (SSc) is a chronic autoimmune rheumatic disease characterized by microvascular alterations, immunopathology, and widespread fibrosis involving various organs. It is considered difficult to treat due to several reasons: complex pathogenesis, heterogeneity, late diagnosis, limited treatment options for certain organ manifestations, lack of personalized medicine.

AREAS COVERED

This review presents the heterogeneity, survival and organ manifestations with their risk factors of systemic sclerosis and their current treatment options, while drawing attention to difficult-to-treat forms of the disease, based on literature indexed in PubMed.

EXPERT OPINION

Despite recent advances in the management of SSc over the last decades, the disease presents significant morbidity and mortality. Although available treatment protocols brought significant advancements in terms of survival in SSc-associated interstitial lung disease and pulmonary arterial hypertension, less success has been achieved in the treatment of Raynaud's phenomenon and digital ulcers and the results are modest in case of heart, gastrointestinal, and renal manifestations. There are patients who do not respond to treatment and deteriorate even with adequate therapy. They can be considered difficult-to treat (D2T) cases. We have created a possible score system based on the individual organ manifestations and highlighted treatment options for the D2T SSc category.

Feasibility of a home-based exercise intervention for patients with systemic sclerosis

INTRODUCTION

Systemic sclerosis (SSc) is a rare connective tissue disease causing pain, reduced mobility and decreased health-related quality of life (HRQoL). Studies suggest that exercise is a necessary adjunct to the medical treatment.

PURPOSE

To examine the feasibility of a 12-week home-based exercise program for SSc patients, and evaluate changes in physical function, HRQoL and SSc-related symptoms.

METHODS

Twenty patients were enrolled in the study. Feasibility was measured by adherence, adverse events, and exercise task self-efficacy. At baseline and follow-up patients completed the 6-minute walk test, 30-second sit-to-stand test, 30-second arm curl, SSc Impact of Disease (ScleroID) and 36-item short form survey (SF-36).

RESULTS

Median adherence to the intervention was 36 (interquartile range 27-36) out of a total of 36 exercise sessions. Fifteen patients completed the intervention, with three dropouts. Patients' exercise task self-efficacy was 98%, 93% and 78%, for one, two and three weekly exercise sessions, respectively. There were no adverse events related to the exercise sessions. Improvements were observed in all physical tests, and minor improvements in HRQoL and SSc-related symptoms.

CONCLUSION

This study suggests that a home-based exercise intervention is feasible for patients with SSc. The results suggest improvements in physical function, HRQoL and SSc-related symptoms.

Association of COVID-19 Vaccinations With Flares of Systemic Rheumatic Disease: A Case-Crossover Study

OBJECTIVE

We aimed to determine the association of COVID-19 vaccination with flares of systemic rheumatic disease (SRD).

METHODS

Adults with systemic rheumatic disease (SRD) in a single-center COVID-19 Rheumatology Registry were invited to enroll in a study of flares. COVID-19 vaccine information from March 5, 2021, to September 6, 2022, was obtained from chart review and self-report. Participants self-reported periods of SRD flare and periods without SRD flare. "Hazard periods" were defined as the time before a self-report of flare and "control periods" as the time before a self-report of no flare. The association between flare and COVID-19 vaccination was evaluated during hazard and control periods through univariate conditional logistic regression stratified by participant, using lookback windows of 2, 7, and 14 days.

RESULTS

A total of 434 participants (mean ± SD age 59 ± 13 years, 84.1% female, 81.8% White, 64.5% with inflammatory arthritis, and 27.0% with connective tissue diseases) contributed to both the hazard and control periods and were included in analysis. A total of 1,316 COVID-19 vaccinations were identified (58.5% Pfizer-BioNTech, 39.5% Moderna, and 1.4% Johnson & Johnson); 96.1% of participants received at least one dose and 93.1% at least two doses. There was no association between COVID-19 vaccination and flares in the subsequent 2, 7, or 14 days (odds ratio [OR] 1.46, 95% confidence interval [CI] 0.86-2.46; OR 1.09, 95% CI 0.76-1.55; and OR 0.85, 95% CI 0.64-1.13, respectively). Analyses stratified on sex, age, SRD subtype, and vaccine manufacturer similarly showed no association between vaccination and flare.

CONCLUSION

COVID-19 vaccination was not associated with flares in this cohort of participants with SRD. These data are reassuring and can inform shared decision-making on COVID-19 immunization.

[Update on targeted biopharmaceuticals in systemic sclerosis!]

Systemic sclerosis (SSc) is a rare connective tissue disease characterized by inflammation, fibrosis, and autoimmunity. Despite few clinical trials when compared to other autoimmune diseases, SSc has benefited from renewed interest over the past ten years and a large number of clinical trials have been performed or are underway. We present here the results of the trials published in the last 5 years in ScS according to the chosen endpoint criteria and describe the trials in progress or expected in the years to come.

Systemic sclerosis interstitial lung disease: unmet needs and potential solutions

Systemic sclerosis (SSc), or scleroderma, is a rare, complex, systemic autoimmune disease of unknown aetiology, characterized by high morbidity and mortality often resulting from cardiopulmonary complications such as interstitial lung disease and pulmonary arterial hypertension. Despite substantial progress in unravelling the pathways involved in the pathogenesis of SSc and the increasing number of therapeutic targets tested in clinical trials, there is still no cure for this disease, although several proposed treatments might limit the involvement of specific organs, thereby slowing the natural history of the disease. A specific focus of recent research has been to address the plethora of unmet needs regarding the global management of SSc-related interstitial lung disease, including its pathogenesis, early diagnosis, risk stratification of patients, appropriate treatment regimens and monitoring of treatment response, as well as the definition of progression and predictors of progression and mortality. More refined stratification of patients on the basis of clinical features, molecular signatures, identification of subpopulations with distinct clinical trajectories and implementation of outcome measures for future clinical trials could also improve therapeutic management strategies, helping to avoid poor outcomes related to lung involvement.

Composite measures to assess disease damage, disease severity and treatment response in systemic sclerosis clinical trials

PURPOSE OF REVIEW

The aim of this study was to summarize the composite outcome measures available to assess disease damage, severity and treatment response in systemic sclerosis (SSc).

RECENT FINDINGS

There have been many recent efforts to rigorously develop and validate composite outcome measures to assess the totality of the impact of SSc on patients. All initiatives have used both consensus and data-driven methods. Recently developed are a SSc-specific damage index, a patient-reported disease impact questionnaire (ScleroID) and a treatment response index (ACR-CRISS).

SUMMARY

Multiorgan, composite measures are being increasingly applied to assess treatment efficacy in clinical trials. Although a fully validated, disease-specific composite measure is not yet available, there has been significant recent progress towards developing measures of treatment response, damage and overall impact of SSc for application in randomized controlled trials.

Patterns of patient-reported symptoms and association with sociodemographic and systemic sclerosis disease characteristics: a scleroderma Patient-centered Intervention Network (SPIN) Cohort cross-sectional study

Background

Systemic sclerosis is a heterogenous disease in which little is known about patterns of patient-reported symptom clusters. We aimed to identify classes of individuals with similar anxiety, depression, fatigue, sleep disturbance, and pain symptoms and to evaluate associated sociodemographic and disease-related characteristics.

Methods

This multi-centre cross-sectional study used baseline data from Scleroderma Patient-centered Intervention Network Cohort participants enrolled from 2014 to 2020. Eligible participants completed the PROMIS-29 v2.0 measure. Latent profile analysis was used to identify homogeneous classes of participants based on patterns of anxiety, depression, fatigue, sleep disturbance, and pain scores. Sociodemographic and disease-related characteristics were compared across classes.

Findings

Among 2212 participants, we identified five classes, including four classes with "Low" (565 participants, 26%), "Normal" (651 participants, 29%), "High" (569 participants, 26%), or "Very High" (193 participants, 9%) symptom levels across all symptoms. Participants in a fifth class, "High Fatigue/Sleep/Pain and Low Anxiety/Depression" (234 participants, 11%) had similar levels of fatigue, sleep disturbance, and pain as in the "High" class but low anxiety and depression symptoms. There were significant and substantive trends in sociodemographic characteristics (age, education, race or ethnicity, marital or partner status) and increasing disease severity (diffuse disease, tendon friction rubs, joint contractures, gastrointestinal symptoms) across severity-based classes. Disease severity and sociodemographic characteristics of "High Fatigue/Sleep/Pain and Low Anxiety/Depression" class participants were similar to the "High" severity class.

Interpretation

Most people with systemic sclerosis can be classified by levels of patient-reported symptoms, which are consistent across symptoms and highly associated with sociodemographic and disease-related variables, except for one group which reports low mental health symptoms despite high levels of other symptoms and substantial disease burden. Studies are needed to better understand resilience in systemic sclerosis and to identify and facilitate implementation of cognitive and behavioural strategies to improve coping and overall quality of life.

Funding

National Institute of Nursing Research (F31NR019007), Canadian Institutes of Health Research, Arthritis Society Canada, the Lady Davis Institute for Medical Research, the Jewish General Hospital Foundation, McGill University, Scleroderma Society of Ontario, Scleroderma Canada, Sclérodermie Québec, Scleroderma Manitoba, Scleroderma Atlantic, Scleroderma Association of BC, Scleroderma SASK, Scleroderma Australia, Scleroderma New South Wales, Scleroderma Victoria, and Scleroderma Queensland.

Characteristics of ScleroID highlighting musculoskeletal and internal organ implications in patients afflicted with systemic sclerosis

BACKGROUND

Systemic sclerosis (SSc) is a multi-organ disease with impaired health-related quality of life (HRQoL). The EULAR SSc Impact of Disease (ScleroID) is a newly introduced SSc-specific patient-reported outcome to evaluate HRQoL in SSc.

OBJECTIVE

To investigate the correlation between the ScleroID and the involvement of organ systems as well as disease activity/damage in a SSc cohort from a large tertiary care centre.

PATIENTS AND METHODS

The ScleroID and clinical characteristics including internal organ involvement and hand function were investigated in 160 consecutive patients with SSc (median age 46 (43;56) years; diffuse cutaneous SSc 55%).

RESULTS

A strong correlation was found between the ScleroID and articular disease activity scores (DAS28-CRP, DAS28-ESR, CDAI, SDAI), a hand function performance test, the Hand Anatomy Index and muscle strength tests. Additionally, a strong significant correlation was discovered using instruments representing hand function and musculoskeletal disability including the Cochin Hand Function Scale, the Quick Questionnaire of the Disability of the Hands, Arms and the Shoulders and the Health Assessment Questionnaire Disability Index. A significant negative correlation was found between the ScleroID score and the 6-min walking test (6MWT) (rho - 0.444, p < 0.001). Clinically mild lung/heart disease did not show increased ScleroID values. The Mouth Handicap in the Scleroderma Scale and the University of California Los Angeles Scleroderma Clinical Trials Consortium gastrointestinal tract 2.0 also showed significant positive correlations to the ScleroID score (rho: 0.626, p < 0.001; rho: 0.646, p < 0.001, respectively). Patients experiencing oesophageal difficulties bore a significantly higher score compared to individuals with a normal functioning oesophagus (3.2/1.5;4.5/ vs. 2.2/1.0;3.2/, p = 0.011). Moreover, the ScleroID showed a significant positive correlation to the revised EUSTAR disease activity index and modified activity index.

CONCLUSION

In a large single-centre cohort, the previously described ScleroID-related findings were confirmed. Furthermore, several organ involvement-related functional and performance tests showed a good correlation to the ScleroID including the 6MWT and gastrointestinal-related complaints. Many aspects of musculoskeletal damage, overall disease activity, pain and fatigue were also well represented in the ScleroID, which efficiently reflects the impact of organ involvement, disease activity and functional damage.

Efficacy and Safety of Botulinum Toxin in Adults with Raynaud's Phenomenon Secondary to Systemic Sclerosis: A Multicenter, Randomized, Double-Blind, Placebo-Controlled Study

OBJECTIVE

To determine whether a single session of botulinum toxin type A (BTA) injections into both hands more effectively decreases the frequency of systemic sclerosis-associated Raynaud's phenomenon (SSc-RP) episodes than placebo.

METHODS

This multicenter, randomized, double-blind, placebo-controlled, parallel-group phase III trial in patients with SSc-RP assessed the effect of 50-unit BTA or placebo injections into the palms of both hands around each neurovascular bundle during 1 session in winter. The primary end point was the between-group difference in the median change in the number of RP episodes from baseline (day 0) to 4 weeks postinjection. Values between the groups were compared with the Wilcoxon rank-sum test.

RESULTS

The intent-to-treat analysis included 46 BTA-treated patients and 44 placebo recipients. At 4 weeks after assigned treatment injections, the median number of daily RP episodes decreased comparably in the BTA and placebo groups (median change -1 episode/day [interquartile range (IQR) -1.5, 0 episodes/day] and -1 episode/day [IQR -2.5, 0 episodes/day], respectively) (P = 0.77 versus placebo). Moreover, change in Raynaud's Condition Score, quality of life assessed by Health Assessment Questionnaire disability index, and hand function assessed by shortened Disabilities of the Arm, Shoulder, and Hand (QuickDASH) and Cochin Hand Function Scale from baseline to follow-up weeks 4, 12, and 24 did not differ significantly between groups. The BTA group experienced transient hand muscle weakness significantly more frequently (P = 0.003).

CONCLUSION

Neither the primary nor secondary end points were reached, and our results do not support any beneficial effect of palmar BTA injections to treat SSc-RP.

Quality Measures in Systemic Sclerosis

Quality improvement is an emerging field, that applies principles of improvement science and utilizes measurement methods with the aim of improving patient care. Systemic sclerosis (SSc) is a systemic autoimmune rheumatic disease associated with increased healthcare burden, cost, morbidity, and mortality. Gaps in delivering care to patients with SSc have been consistently observed. In this article, we introduce the discipline of quality improvement and its use of quality measures. We summarize and comparatively evaluate three sets of quality measures that have been proposed to evaluate the quality of care of patients with SSc. Finally, we highlight the areas of unmet needs and indicate future directions for quality improvement and quality measures in SSc.

Assessment of disease outcome measures in systemic sclerosis

The assessment of disease activity in systemic sclerosis (SSc) is challenging owing to its heterogeneous manifestations across multiple organ systems, the variable rate of disease progression and regression, and the relative paucity of patients in early-phase therapeutic trials. Despite some recent successes, most clinical trials have failed to show efficacy, underscoring the need for improved outcome measures linked directly to disease pathogenesis, particularly applicable for biomarker studies focused on skin disease. Current outcome measures in SSc-associated interstitial lung disease and SSc skin disease are largely adequate, although advancing imaging technology and the incorporation of skin mRNA biomarkers might provide opportunities for earlier detection of the therapeutic effect. Biomarkers can further inform pathogenesis, enabling early phase trials to act as reverse translational studies through the incorporation of routine high-throughput sequencing.