Long-term follow-up study of 164 patients with definite systemic sclerosis: classification considerations

Systematic Analysis of the Literature in Search of Defining Systemic Sclerosis Subsets

OBJECTIVE

Systemic sclerosis (SSc) is a multisystem disease with heterogeneity in presentation and prognosis.An international collaboration to develop new SSc subset criteria is underway. Our objectives were to identify systems of SSc subset classification and synthesize novel concepts to inform development of new criteria.

METHODS

Medline, Cochrane MEDLINE, the Cumulative Index to Nursing and Allied Health Literature, EMBASE, and Web of Science were searched from their inceptions to December 2019 for studies related to SSc subclassification, limited to humans and without language or sample size restrictions.

RESULTS

Of 5686 citations, 102 studies reported original data on SSc subsets. Subset classification systems relied on extent of skin involvement and/or SSc-specific autoantibodies (n = 61), nailfold capillary patterns (n = 29), and molecular, genomic, and cellular patterns (n = 12). While some systems of subset classification confer prognostic value for clinical phenotype, severity, and mortality, only subsetting by gene expression signatures in tissue samples has been associated with response to therapy.

CONCLUSION

Subsetting on extent of skin involvement remains important. Novel disease attributes including SSc-specific autoantibodies, nailfold capillary patterns, and tissue gene expression signatures have been proposed as innovative means of SSc subsetting.

[The road to early diagnosis of systemic sclerosis : the evolution of diagnostic and classification criteria in the past decades]

Increasing knowledge about the rare disease systemic sclerosis (SSc) and improved diagnostic methods in recent decades has led to the possibility of diagnosing systemic sclerosis in earlier disease stages. In this review, we describe the evolution of diagnostic and classification criteria for SSc, beginning with the preliminary ARA criteria for the classification of SSc in 1980, then presenting the criteria for limited and diffuse cutaneous SSc by LeRoy et al. in 1988 and 2001, and finishing with a discussion of the recently published new ACR-EULAR classification criteria in 2013. In addition, we seize the ongoing discussion about the intermediate subtype of SSc and highlight whether the two special subtypes CREST syndrome as well as SSc sine scleroderma are similar or different from the limited cutaneous SSc subtype. Finally, we address the question when a patient should be referred to the rheumatologist and discuss potential red flags for early diagnosis of systemic sclerosis.

The degree of skin involvement identifies distinct lung disease outcomes and survival in systemic sclerosis

OBJECTIVE

To determine whether the pattern of skin involvement can predict clinical features, risk of restrictive lung disease (RLD) and survival in a large scleroderma (SSc) cohort.

METHODS

Demographic and clinical data collected over 30 years from 2205 patients with SSc were retrospectively analysed after subdividing subjects into four subtypes based on pattern of skin fibrosis: type 0 (no skin involvement), type 1 (limited to metacarpophalangeal joints), type 2 (distal to elbows/knees) and type 3 (proximal to elbows/knees). Clinical features associated with skin subsets were identified by regression analyses. Kaplan-Meier and Cox proportional hazards models were used to compare time to RLD and survival across subtypes.

RESULTS

The presence and severity of RLD were positively associated with skin subtype (p<0.001). RLD prevalence incrementally ranged from 51.9% in type 0 to 76.7% in type 3 (p<0.001). Type 2 SSc exhibited a distinct phenotype with intermediate risk for RLD relative to type 1 (higher, p<0.001) and type 3 (lower, p<0.001) and a unique autoantibody profile, with a prevalence of anticentromere antibodies lower than type 1 (28.9% vs 44.1%, p=0.001) and of anti-topoisomerase I antibodies similar to type 3 (32.8% vs 28.7%, p=0.38). These autoantibodies were also found to be significant negative (OR=0.33, p<0.001) and positive (OR=1.6, p=0.01) predictors of RLD risk, respectively. Mortality was also intermediate in type 2 patients relative to type 3 (p=0.0003) and type 1 (p=0.066).

CONCLUSIONS

These data suggest that the current classification subdividing SSc into limited and diffuse cutaneous subtypes misclassifies an intermediate group of patients exhibiting unique autoantibody profile, disease course and clinical outcomes.

The development of systemic sclerosis classification criteria

Systemic sclerosis (SSc) is a rare connective tissue disorder whose aetiology remains obscure, although environmental and genetic influences are likely to play a role. Disease registries have contributed to enhancing our understanding of this debilitating illness, but without sensitive, specific, and extensively validated classification criteria, accurate comparison between registries and the identification of patients suitable for clinical trials can be problematic. The American College of Rheumatology (ACR) criteria, published in 1980, have become outdated as our understanding of disease specific autoantibodies and nailfold capillaroscopy has improved. In addition, the sensitivity of the ACR criteria is low with respect to limited SSc. Although subsequent classification systems have been proposed, none has gained universal approval. The two- versus three-subset disease model remains a point of debate. Newly derived criteria are likely to draw upon the older classification systems as well as incorporating up-to-date diagnostic techniques and biomarkers. Validation will be critical before their use becomes widespread.

Autoantibodies in SLE but not in scleroderma react with protein-stripped nucleosomes

Autoantibodies against nucleosomes (ANuA) are known to be sensitive markers for systemic lupus erythematosus (SLE), but their clinical relevance seemed to be limited because sera from patients with progressive systemic sclerosis (PSS) also showed positive reactions with conventional ANuA ELISA test systems (anti-Nu1 ELISA). It was generally assumed thatANuA were associated with both diseases. Using discontinuous sucrose gradient centrifugation to generate pure nucleosomes, we discovered by chance that at the 30-50% sucrose interface an antigen (Nu2) banded which was demonstrably free of non-histone components and histone H1. The two different nucleosome preparations, Nu1 and Nu2, were used in parallel as antigenic substrates in standardised ELISA tests to analyse sera from SLE (295 patients), PSS (119) and patients with other rheumatic diseases (101). With Nu1, 62% of the SLE and 52% of the PSS sera showed positive reactions. Two sera from patients suffering from Sjögren's syndrome (SS) and one from polymyositis were also positive. Using the Nu2 preparation, 58% of the SLE but none of the PSS sera showed a positive reaction. One serum from a patient with SS was also positive. It could be shown that it was the PSS-specific autoantigen Scl-70 in the nucleosome preparation (Nu1) which contributed to the positive reactions of the PSS sera in conventional ANuA test systems, whereas in the Nu2 preparation no remaining Scl-70 was detectable. The present study definitely proved that ANuA are highly and specifically associated with SLE but not with PSS.

European multicentre study to define disease activity criteria for systemic sclerosis. I. Clinical and epidemiological features of 290 patients from 19 centres

OBJECTIVE

To investigate the existence of differences among European referral centres for systemic sclerosis (SSc) in the pattern of attendance and referral and in the clinical and therapeutical approaches.

METHODS

In 1995 the European Scleroderma Study Group initiated a multicentre prospective one year study whose aim was to define the disease activity criteria in SSc. During the study period each participating European centre was asked to enroll consecutive patients satisfying American College of Rheumatology criteria for SSc and to fill out for each of them a standardised clinical chart. Patients from various centres were compared and differences in epidemiological, clinical, and therapeutical aspects were analysed.

RESULTS

Nineteen different medical research centres consecutively recruited 290 patients. The patients could be divided into two subgroups: 173 with the limited (lSSc) and 117 with the diffuse (dSSc) form of the disease. The clinical and serological findings for the series of 290 patients seemed to be similar to data previously reported. However, when the data were analysed to elicit any differences between the participating centres, a high degree of variability emerged, in both epidemiological and clinical features and in the diagnostic and therapeutic approaches to the disease.

CONCLUSIONS

The clinical approach to SSc, not only in different countries but also in different centres within the same country, is not yet standardised. To overcome this problem, it will be necessary for the scientific community to draw up a standardised procedure for the management of patients with SSc. This would provide a common research tool for different centres engaged in research on this complex disease.

[Pulmonary involvement in systemic scleroderma. Part I. Chronic fibrosing interstitial lung disease]

INTRODUCTION

Chronic pulmonary interstitial fibrosis is the most frequent respiratory manifestation in systemic sclerosis, occurring in 80% of cases. It remains a severe complication of the disease and is the primary cause of mortality related to respiratory insufficiency in 20 to 60% of cases.

CURRENT KNOWLEDGE AND KEY POINTS

The date of onset of interstitial lung disease remains undetermined, and only in rare cases does it reveal the presence of systemic sclerosis. The clinical signs are only observable at a later stage, when at least 50% of the lung parenchyma is affected. The methods of choice adopted for early diagnosis of this disease are high resolution computed tomography and pulmonary functional investigations; they should be carried out during the preliminary investigation and at follow-up once a year. Moreover, high resolution computed tomography also provides prognostic data, for there is a correlation between the type of lesion and its severity as determined by high resolution computed tomography and by histological findings. The value of other methods of investigation, in particular bronchoalveolar lavage, has not yet been clearly established. The association of cyclophosphamide and corticoids is currently being evaluated (indications, administration modalities, duration), and this combination may be the most effective treatment.

FUTURE PROSPECTS AND PROJECTS

Interstitial lung disease is one of the major causes of morbidity and mortality in systemic sclerosis. Early diagnosis and management of this disease is therefore of utmost importance.

Mortality and causes of death in a Swedish series of systemic sclerosis patients

OBJECTIVES

To analyse survival rates and the causes of death in a systemic sclerosis (SSc) population, and to evaluate the occurrence of fatal malignant neoplasms and their possible association with oral cyclophosphamide (CYC) treatment.

METHODS

Survival was calculated for 249 SSc patients followed up for up to 13 years. Mean (SD) follow up was 5.8 (4.2) years. The 49 decreased patients were subdivided according to causes of death and its relation to SSc. Fatal malignancies in CYC treated patients were compared with those occurring in non-CYC treated patients.

RESULTS

The overall 5 and 10 year survival rates were 86% and 69% respectively. There was a 4.6-fold increased risk of death, as compared with the general population. Prognosis was worse in the diffuse cutaneous involvement (dSSc) and male subgroups than in the limited cutaneous involvement (1SSc) and female subgroups. Of the 49 deaths, 24 were attributable to pulmonary complications such as pulmonary fibrosis, pulmonary hypertension, pneumonia or pulmonary malignancy. Treatment with oral CYC did not increase the risk of dying of cancer.

CONCLUSIONS

Mortality is increased both in the SSc population as a whole and in its different subsets (dSSc and 1SSc). Prognosis is worst among male patients with dSSc. However, the 5 year survival rate was better than those reported from earlier studies. Most patients die of cardiopulmonary disease. Five of seven fatal lung cancers were adenocarcinomas, possibly caused by chronic inflammatory disease of the lung. In this study, CYC treatment was not associated with an increased incidence of fatal malignant neoplasms.

Racial differences in scleroderma among women in Michigan

OBJECTIVE

To examine racial differences in disease onset, extent, manifestations, and survival among women with scleroderma.

METHODS

A retrospective cohort study of women with scleroderma, diagnosed in Michigan between 1980 and 1991, was conducted. Clinical, laboratory, and demographic data were abstracted from the patients' medical records.

RESULTS

A total of 514 women with scleroderma were identified: 117 (23%) were black and 397 (77%) were white. Among black women, the mean age at diagnosis was lower (44.5 years versus 51.5 years; P < 0.001) and diffuse disease was more common (49.6% versus 24.9%; P < 0.001) than among white women. The overall incidence of scleroderma was 14.1 per million per year: 22.5 per million per year in black women versus 12.8 per million per year in white women (P < 0.001). Pericarditis (P = 0.009), pulmonary hypertension (P < 0.001), pleural effusions (P = 0.01), myositis (P = 0.02), and an erythrocyte sedimentation rate >40 mm/hour (P < 0.001) were more frequent among black women, while white women were more likely to have digital infarctions (P < 0.001). Survival at 7 years from diagnosis was 72.5% among black women and 77.6% among white women. Age-adjusted survival was significantly reduced among black women (P = 0.033), most likely because of increased diffuse involvement. Survival among those with renal or pulmonary involvement was also significantly reduced.

CONCLUSION

Black women with scleroderma were significantly more likely than white women to develop diffuse disease, be diagnosed at a younger age, have a higher incidence of inflammatory features, and have a worse age-adjusted survival rate.

Epidemiology of systemic sclerosis

Systemic sclerosis is a family of disorders most appropriately considered in the category of the connective tissue diseases. Two major forms are recognized (diffuse cutaneous and limited cutaneous involvement subtypes), each with distinctive clinical and serologic findings as well as natural history. Scleroderma is characterized epidemiologically by several distinctive features. From a demographic viewpoint, the disease spares children and its incidence increases steadily with age among adults. If occurs much more frequently in women, especially during the child-bearing years, and most often and most severely in young black women, though there is no overall prominent racial predilection. The annual incidence approaches 20 per million population, and may be considerably underestimated. Both incidence and mortality have increased during the past several decades, but these changes are most likely a result of improved case detection rather than a true increase in incidence. Prevalence studies have not been undertaken, but 500 per million population may be a reasonable estimate. Family and genetic studies suggest a weak genetic predisposition, but several strong HLA associations with scleroderma-specific serum autoantibodies are evident. Certain environmental agents may be implicated in pathogenesis of scleroderma and closely related systemic illnesses associated with cutaneous fibrosis. The widespread pathologic process in systemic sclerosis leads to vascular insufficiency and fibrosis, which diminishes the reserve function of many organ systems. The result is considerable disability, especially affecting hand function, and a significant reduction in life span, with an overall 10-year survival from first physician diagnosis of under 70%. Further epidemiologic studies should take full advantage of established and newly proposed subsets of patients with homogeneous clinical, laboratory, serologic, and natural history features. The environment-host interactions noted here must be fully explored, especially in early untreated disease, where primary rather than secondary mechanisms are most likely to be operative.