Measures of disease status in systemic sclerosis: A systematic review

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.

Application and performance of disease activity indices proposed for patients with systemic sclerosis in an international cohort of patients with juvenile systemic sclerosis

Objectives

Juvenile systemic sclerosis is a rare childhood disease. Three disease activity indices have been published for adult patients with systemic sclerosis: the European Scleroderma Study Group Index, a modified version of the European Scleroderma Study Group Index and the revised European Scleroderma Trials and Research index. The objective of this study was to determine the feasibility and performance of the three disease activity indices in a prospectively followed cohort of patients with juvenile systemic sclerosis.

Methods

The analysis cohort was selected from the prospective international inception cohort enrolling juvenile systemic sclerosis patients. The correlation of the disease activity indices with the physicians' and the patients' global assessment of disease activity was determined. The disease activity indices were compared between patients with active and inactive disease. Sensitivity to change between 6- and 12-month follow-up was investigated by mixed models.

Results

Eighty percent of the 70 patients had a diffuse cutaneous subtype. The revised European Scleroderma Trials and Research index was highly correlated with the physician-reported global disease activity/parents-reported global disease activity (r = 0.74/0.64), followed by the European Scleroderma Study Group activity index (r = 0.61/0.55) and the modified version of the European Scleroderma Study Group activity index (r = 0.51/0.43). The disease activity indices significantly differed between active and inactive patients. The disease activity indices showed sensitivity to change between 6- and 12-month follow-up among patients who improved or worsened according to the physician-reported global disease activity and the parents-reported global disease activity.

Conclusion

Overall, no disease activity score is superior to the other, and all three scores have limitations in the application in juvenile systemic sclerosis patients. Furthermore, research on the concept of disease activity and suitable scores to measure disease activity in patients with juvenile systemic sclerosis is necessary in future.

The economic burden of systemic sclerosis-A systematic review

AIM

Systemic sclerosis (SSc) is a rare, chronic autoimmune disease associated with a substantial economic burden. This study aimed to assess the costs associated with SSc and to identify major cost drivers.

METHODS

A systematic search was conducted in MEDLINE and Embase to identify relevant studies. Two independent reviewers evaluated studies based on inclusion/exclusion criteria and performed data extraction. Costs were converted into 2017 US dollars by purchasing power parity. The review was conducted following the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guideline.

RESULTS

The original literature search identified 113 potentially relevant citations, of which 10 articles met all the inclusion/exclusion criteria and were included in the data extraction and analysis. The identified studies evaluated costs associated with SSc in 11 countries from North America, Europe, and Australia published between 2009 and 2018. Eight studies reported direct costs and seven studies reported indirect costs. Direct costs varied from $3356 (Hungary) to $27 032 (Germany) with hospitalization and medication being two of the biggest components of direct medical costs in most studies. The indirect costs for lost productivity varied from $2433 (Italy) to $20 663 (UK), accounting for a significant portion of the total economic burden.

CONCLUSIONS

Large variations existed in annual costs of SSc, but all studies found that SSc imposed a substantial economic burden on patients and their families. The identified studies were mostly from high-income countries and there is still a knowledge gap regarding the cost of SSc in other parts of the world.

Validity and reliability of the Swedish version of the Self-Efficacy for Managing Chronic Disease scale for individuals with systemic sclerosis

ObjectiveTo investigate aspects of validity and reliability of the Swedish version of the Self-Efficacy for Managing Chronic Disease (SEMCD-Swe) scale in systemic sclerosis (SSc).Method: A forward-backward translation procedure was used. Content validity was assessed through interviews with 11 people with SSc and 10 healthcare professionals. Construct validity, internal consistency, test-retest reliability, and floor and ceiling effects were evaluated in 104 SSc patients.Results: The content validity of the SEMCD-Swe was interpreted as satisfactory, but some adjustments were made to increase the understanding. Confirmatory factor analysis supported a single-factor structure. Moderate to strong correlations between the SEMCD-Swe and Scleroderma Health Assessment Questionnaire; Multidimensional Assessment of Fatigue; Patient Health Questionnaire-8 (r_s = -0.4 to -0.7), and RAND-36 subscales (r_s = 0.5 to 0.7) were found. Weak correlations were found between SEMCD-Swe and modified Rodnan skin score; and disease severity of peripheral vascular and lung (r_s = -0.1 to -0.2) and kidney (r_s = 0.1) systems (Medsger severity scale). Cronbach's alpha was sufficient (0.85) and corrected item-to-total correlations were good (≥ 0.50). The intraclass correlation coefficient for the total score was sufficient (0.82). No floor or ceiling effects were found.Conclusion: Support for construct validity was indicated, as the SEMCD-Swe in SSc show a single-factor structure and is more strongly associated with pain, fatigue, depressive symptoms, interferences with daily activities, disability, and quality of life than with disease severity. Our results also indicate support for content validity and reliability. However, the responsiveness of the SEMCD-Swe needs to be tested.

Muscle Damage in Systemic Sclerosis and CXCL10: The Potential Therapeutic Role of PDE5 Inhibition

Skeletal muscle damage is a common clinical manifestation of systemic sclerosis (SSc). C-X-C chemokine ligand 10 (CXCL10) is involved in myopathy and cardiomyopathy development and is associated with a more severe SSc prognosis. Interestingly, the phosphodiesterase type 5 inhibitor (PDE5i) sildenafil reduces CXCL10 sera levels of patients with diabetic cardiomyopathy and in cardiomyocytes. Here, we analyzed the levels of CXCL10 in the sera of 116 SSc vs. 35 healthy subjects and explored differences in 17 SSc patients on stable treatment with sildenafil. CXCL10 sera levels were three-fold higher in SSc vs. healthy controls, independent of subset and antibody positivity. Sildenafil treatment was associated with lower CXCL10 sera levels. Serum CXCL10 strongly correlated with the clinical severity of muscle involvement and with creatine kinase (CK) serum concentration, suggesting a potential involvement in muscle damage in SSc. In vitro, sildenafil dose-dependently reduced CXCL10 release by activated myocytes and impaired cytokine-induced Signal transducer and activator of transcription 1 (STAT1), Nuclear factor-κB (NFκB) and c-Jun N-terminal kinase (JNK) phosphorylation. This was also seen in cardiomyocytes. Sildenafil-induced CXCL10 inhibition at the systemic and human muscle cell level supports the hypothesis that PDE5i could be a potential therapeutic therapy to prevent and treat muscle damage in SSc.

Can Patient-Reported Symptoms Be Used to Measure Disease Activity in Systemic Sclerosis?

OBJECTIVE

To evaluate the association between patient-reported symptoms and changes in disease activity over time in systemic sclerosis (SSc).

METHODS

Using data from 1,636 patients enrolled in the Australian Scleroderma Cohort Study, we used generalized estimating equations to determine the relationship between patient-reported worsening of Raynaud's phenomenon (RP), skin involvement, and breathlessness in the month preceding each study visit and features of disease activity in the corresponding organ systems. The associations between the following parameters were analyzed: patient-reported worsening RP and the presence of new-onset digital pitting and digital ulcers; patient-reported worsening skin involvement and increasing modified Rodnan skin thickness score (MRSS); new areas of skin involvement and new-onset joint contractures; patient-reported worsening breathlessness and deteriorating respiratory functions test (RFT) results, indicated by a 10% decrease in forced vital capacity (FVC) and a 15% decrease in diffusing capacity for carbon monoxide (DLco), new-onset interstitial lung disease (ILD), and new-onset pulmonary arterial hypertension (PAH).

RESULTS

We found a significant association between patient-reported worsening RP and the presence of digital ulcers (odds ratio [OR] 1.53 [95% confidence interval (95% CI) 0.60-0.93]), patient-reported worsening skin involvement and increasing MRSS (OR 2.10 [95% CI 1.54-2.86]), and worsening patient breathlessness and deteriorating RFTs (FVC OR 2.12 [95% CI 1.70-2.65]; DLco OR 1.97 [95% CI 1.34-2.02]), new-onset ILD (OR 1.91 [95% CI 1.40-2.61]), and new-onset PAH (OR 5.08 [95% CI 3.59-7.19]).

CONCLUSION

These results demonstrate that patient-reported symptoms are associated with clinically meaningful changes in disease activity in patients with SSc. This suggests that when objective measures of change in disease status are unavailable, patient-reported symptoms could be used to indicate a change in SSc disease activity.

Validity and reliability of the Patient Health Questionnaire-8 in Swedish for individuals with systemic sclerosis

Background

Depressive symptoms are common in rheumatic diseases and influence patients’ quality of life. The Patient Health Questionnaire-9 (PHQ-9), which assesses symptoms of depression, is valid in English in patients with systemic sclerosis (SSc). However, the measurement properties of the PHQ-8 (short version of the PHQ-9) have not been evaluated in Swedish patients with SSc.

Objective

To investigate different aspects of validity and reliability of the PHQ-8 in Swedish (PHQ-8 Swe) for individuals with SSc.

Methods

A total of 101 patients with SSc participated. Content validity was evaluated via interviews of 11 patients and 10 health professionals. Construct validity, internal consistency test–retest reliability, and floor/ceiling effects were evaluated in 90 patients.

Results

Content validity was satisfactory, but some linguistic adjustments were made. Confirmatory factor analysis supported a better fit for a two-factor structure. Moderate-to-strong correlations were found between the PHQ-8 Swe and scleroderma HAQ including VAS (r_s = 0.4–0.7); Multidimensional Assessment of Fatigue (r_s = 0.7); RAND-36 subscales (r_s = − 0.5 to − 0.8); and lung disease severity (Medsger scores) (r_s = 0.4). There were weak correlations (r_s = <0.4) between the PHQ-8 Swe and modified Rodnan skin score; and vascular, heart, and kidney disease severity. Cronbach’s alpha was 0.85, corrected item-to-total correlations were >0.40, and the ICC for the total score was 0.83. No floor/ceiling effects were found.

Conclusion

The PHQ-8 Swe has satisfactory content validity and sufficient reliability in patients with in majority limited SSc. It is more strongly associated with self-reported disability, pain, disease interferences with daily activities, fatigue, and quality of life than with disease severity, except for a moderate association with lung severity.

Immunosuppressive treatment in diffuse cutaneous systemic sclerosis is associated with an improved composite response index (CRISS)

Background

Outcomes of therapeutic studies in diffuse cutaneous systemic sclerosis (dcSSc) have mainly been measured for specific organs, particularly the skin and lungs. A new composite response index in dcSSc (CRISS) has been developed for clinical trials. The goal of this study was to determine whether, in an observational dcSSc cohort, immunosuppression was associated with global disease improvement measured with the CRISS.

Methods

We conducted a retrospective cohort study in a multi-centered SSc registry comparing 47 patients newly exposed to immunosuppression for ≥ 1 year to 254 unexposed patients. Inverse probability of treatment weighting (IPTW) was performed to create comparable exposed and unexposed groups by balancing for age, sex, disease duration, modified Rodnan skin score (mRSS), forced vital capacity, patient and physician global assessments, and Health Assessment Questionnaire score. A CRISS score ≥ 0.6 at 1 year was defined as improvement.

Results

Exposed patients had shorter disease duration (5.5 versus 11.7 years, p < 0.01), more interstitial lung disease (67.4% versus 40.3%, p < 0.01), and worse physician global severity scores (4.2 versus 2.5 points, p < 0.01) compared to unexposed patients. Improvement in CRISS scores was more common in exposed patients after IPTW (odds ratio 1.85, 95% confidence interval 1.11, 3.09). Of the individual CRISS variables, only mean patient global assessment scores were significantly better among exposed than unexposed patients (− 0.4 versus 0 points, p = 0.03) while other variables including mRSS were similar.

Conclusion

Using a composite response measure, immunosuppression was associated with better outcomes at 1 year in a dcSSc cohort. These results provide real-world data that align with clinical trials to support our current use of immunosuppression.

Scleroderma Renal Crisis Debute with Thrombotic Microangiopathy: A Successful Case Treated with Eculizumab

We had the challenged to treat a 40-year-old female with Systemic Scleroderma who was showing unspecific symptoms. During her time at the hospital she rapidly develops renal dysfunction, associated with hypertension. She required renal replacement therapy initiation and we observed a decline in hemoglobin and platelets numbers. We confirm a microangiopathic hemolytic anemia and rule out other immune diseases or thrombotic thrombocytopenic purpura. Systemic Sclerosis is a chronic immune disorder of unknown origin that it is not completely understood. It is believed that environmental factors may contribute and also altered genes may be implicated in the immune system's function. Microangiopathic hemolytic anemia occurs in 43% of patients who develop scleroderma renal crisis and an activation of the complement system through the classical pathway may be involved. Given that context we decided to treat the patients with C5 blocker Eculizumab and obtain an extraordinary positive response.

An Interim Report of the Scleroderma Clinical Trials Consortium Working Groups

The Scleroderma Clinical Trials Consortium (SCTC) represents many of the clinical researchers in the world who are interested in improving the efficiency of clinical trials in Systemic Sclerosis (SSc). The SCTC has established 11 working groups (WGs) to develop and validate better ways of measuring and recording multiple aspects of this heterogeneous disease. These include groups working on arthritis, disease damage, disease activity, cardiac disease, juvenile SSc, the gastrointestinal tract, vascular component, calcinosis, scleroderma renal crisis, interstitial lung disease, and skin measurement. Members of the SCTC may join any one or more of these groups. Some of the WGs have only recently started their work, some are nearing completion of their mandated tasks and others are in the midst of their projects. All these projects, which are described in this paper, will help to improve clinical trials and observational studies by improving or developing better, more sensitive ways of measuring various aspects of the disease. As Lord Kelvin stated, "To measure is to know. If you cannot measure it you cannot improve it." The SCTC is dedicated to improving the lives of patients with SSc and it is our hope that the contributions of the WGs will be one important step in this process.

The challenges and controversies of measuring disease activity in systemic sclerosis

Major alteration of the natural history of systemic sclerosis is limited with current treatments, and the development of novel therapies has been hampered, in part, by the lack of fully validated multi-system outcome measures. There remains a lack of consensus as to the very definition of systemic sclerosis disease activity, complicating efforts to measure activity in clinical trials. Previously published multi-system measures of disease status are yet to be fully validated according to the Outcome Measures in Rheumatology (OMERACT) filter. There is currently significant research interest in developing new systemic sclerosis-specific measures to better describe and compare patient cohorts and measure therapeutic responses in clinical trials. An accurate measure of disease activity in systemic sclerosis will facilitate the enrichment of clinical trials with patients who have active disease, targeting a group of patients most likely to benefit from therapeutic intervention. In addition, following on from successes in other rheumatic conditions, a state of low disease activity, measured by an activity index, may become a clinical trial end point and therapeutic target. The Scleroderma Clinical Trials Consortium has undertaken to develop a definition of disease activity and fully validate a new systemic sclerosis activity index. The Scleroderma Clinical Trials Consortium Activity Index will be developed using consensus and data-driven methods and is envisaged to be widely used in research and clinical settings.

Systemic sclerosis and the gastrointestinal tract

Systemic sclerosis (SSc) is an autoimmunological disease of unknown origin with complex pathogenesis and multiple organ involvement. It is characterised by vascular and immunological abnormalities leading to fibrosis of the skin and internal organs. It is a rather rare disease with a prevalence of around 20 per 100,000. The disease results in heterogeneous clinical findings and different courses. Systemic sclerosis usually begins with the onset of Raynaud’s phenomenon (RP), followed by skin sclerosis and internal organ involvement, although it may appear synchronously with RP. Gastrointestinal involvement is a serious and prevalent complication of SSc, and the oesophagus is the most frequently affected organ. Both limited and diffuse cutaneous SSc involve internal organs, with the involvement of the gastrointestinal tract as a leading cause of morbidity. At present, treatment is mainly symptomatic with no disease-modifying drugs.