Disease Characteristics of the Singapore Systemic Sclerosis Cohort

Abstract

Introduction: Systemic sclerosis (SSc) has one of the worst prognoses among autoimmune diseases. Multi-ethnic Western cohorts have shown ethnic differences in disease characteristics. Due to a paucity of data in Asia, we aimed to describe the disease characteristics and autoantibody profile of Asian SSc patients. Methods: The Singapore SSc database consists of prevalent and incident cases from four institutions. Data were recorded annually according to a standardised protocol. Cumulative disease characteristics were analysed using descriptive statistics. Results: From 2008 to 2012, 200 patients (85.5% females; Chinese 78%, Malays 10.5%, Indians 6%) diagnosed at a mean age of 46 years, fulfilled the American College of Rheumatology (ACR) (88.0%) or the Very Early Diagnosis of SSc (VEDOSS) (12%) criteria. SSc subtypes include limited cutaneous SSc (LcSSc) (32%) or diffuse cutaneous SSc (DcSSc) (37.6%), SSc-overlap syndromes (27.4%) and sine scleroderma (3%). Predominant disease manifestations were Raynaud's phenomenon (n=161, 80.5%), gastrointestinal (GI) (n=125, 62.5%), joint pain (n=116, 58%) and interstitial lung disease (ILD) (n=99, 51.8%). Pulmonary arterial hypertension (PAH) by echocardiography was present in 23.2% (39/168) of patients (mean systolic pulmonary arterial pressure 55.0+19.7mmHg). Renal crisis was rare (n=4, 2%). Anti-nuclear antibodies (ANA) tested positive in 78.7% (155/197), with anti-Scl-70 (69/197, 35.0%), anti-ribonucleoprotein (RNP) (56/192, 29.2%) and anti-Ro60 (40/193, 20.7%) most frequently detected. Anti-centromere antibodies were infrequent (23/190, 12.1%). Treatment included corticosteroids (80.7%), for peripheral vasculopathy (61.4%), GI (68%), PAH (11.2%) and immunosuppression (62.9%). Conclusion: Compared to Caucasian patients, our predominantly Chinese Asian SSc patients were diagnosed at an earlier age, with more severe PAH, less frequent Raynaud's phenomenon, an autoantibody profile characterised by anti-Scl70, anti-RNP and anti-Ro60, infrequently anti-centromere and more patients had DcSSc.

Comparison of the clinical phenotype of systemic sclerosis patients in Iran and France in two university centers

“…The female-to-male ratio was reported ranging from 1:1 to 14:1 in different studies. 22 In this work, this ratio was approximately 5:1, which is similar to the data in EUSTAR database (6:1) 16 and certain Asian countries, 5,14,20,23 indeed the more female predominance was reported in Turkey and Japan with the female-to-male ratio of 13:1 and 10:1, respectively. 6,15 Regarding the comparison of auto-antibody profiles, the Iranian patients were more seropositive for ATA, whereas the French cases had higher level of ACA.…”

“…According to the report of Singapore SSc cohort, SSc patients had higher prevalence of diffuse cutaneous systemic sclerosis (dcSSc), more severe pulmonary arterial hypertension (PAH), and lower disease onset age than non-Asian population. 5 In line with this study, the frequency of dcSSc and female disease onset age in Japanese cohort, is partially similar to mentioned cohort but the auto-antibodies profile was divergent. 6 As it was indicated, ethnicity-dependent variations in SSc clinical spectrum take us a guide to better investigate the areas which contribute more deeply in SSc development.…”

“…Its prevalence in the French population was compatible with previously reported works on Europeans, but its distribution is variable among Asian countries ranging from 12% in Singapore to 40% in Japan. 5,6,15,16,20 In our study, the ATA and ACA prevalence was not different in dcSSc patients, but the differences among lcSSc group seem to be related to genetic factors which need further investigations. The prevalence of ARA was 4.6% in French patients and 2% in Iranians.…”

“…4 However, reports from the Asian cohorts indicate the age at onset of 39 years in Malaysia, 46 years in Singapore, 47 years in Japan, 49 years in Thailand and Turkey, and 51 years in Taiwan. 5,6,[12][13][14][15] Moreover, the mean age at onset of Raynaud's phenomenon (RP) and first non-RP were 42 and 46 years, respectively, in EUSTAR cohort. 16 According to these results, although it seems that the age at onset is lower in Asian countries, the Iranians affect at younger ages which appears to be significantly different from its Asian counterparts.…”

“…33 On the contrary, PAH was reported more frequently in Asian countries, ranging from 16% in Japan, 20% in Iraq, 24% in Singapore, 32% in India, 43% in Turkey, and 59% in Thailand. 5,6,15,[34][35][36] It must be pointed out that these variable results can be related to different detection method and dissimilar definitions for PAH, although it is established that only right heart catheterization can provide a meaningful diagnosis. 37 In general, it seems that probable PAH was detected less frequently in Iranian patients than in other Asian countries.…”