Background/Purpose: The 2013 ACR/EULAR classification criteria for systemic sclerosis (SSc) allowed the inclusion of a subset of patients without skin involvement, not considered by the 1980 criteria. As the severity and the prognosis of these patients are still controversial, a pragmatic approach to characterize them according to the severity of visceral involvement is useful in the current daily practice.

Methods: Consecutive patients classified as SSc according to 2013 ACR/EULAR criteria attended in a single scleroderma outpatient clinic between 2010 and 2018 were included. Overlap syndromes were excluded.  Patients with SSc skin involvement were classified as diffuse (dSSc) and limited (lSSc) according to LeRoy criteria. Patients without skin thickness were divided in two distinct groups: visceral sine-scleroderma (vsSSc) and non-visceral sine scleroderma (nvsSSc).  VsSSc was considered in the presence of: a) Interstitial lung disease (ILD) [ground-glass > 10% in chest high resolution computed tomography (HRCT) or forced vital capacity < 70%]; b) Pulmonary arterial hypertension (PAH) confirmed by right heart catheterization; c) Heart (symptomatic arrhythmia, pericarditis or congestive heart failure); d) Kidney (scleroderma renal crisis). Clinical and laboratory data were obtained from an electronic register database. Proper statistics tests were applied and considered significant when p< 0.05. Log-Rank test was used to compare the survival curves.

Results: The cohort comprised 638 patients, 27.3% dSSc, 50.5% lSSc, 13.3% vsSSc, and 8.9% nvsSSc. Patients with skin involvement had longer disease duration and time of follow-up when compared to vsSS and nvsSSc(p< 0.001).  As expected, patients with vsSSc presented a predominant clinical picture of ILD(85.9% of any ground-glass and 42.4% of >10% ground-glass in chest HRCT) or PAH(29.4%). Remarkably, the frequency of ILD in vsSSc was similar to dSSc(p=0.95), and PAH was more common in vsSSc than in any other subset(p< 0.01). Although cardiac(23.5%) and renal(2.4%) involvement were observed, they were never referred as a SSc initial symptom in the vsSSc subgroup. In the other hand, nvsSSc also presented a lower frequency(36.8%,p< 0.001) of ILD(all with < 10% of ground-glass in chest HRCT). These nvsSSc patients were predominantly women with higher frequencies of SD pattern at the nailfold capillaroscopy(98.1%,p=0.03) and anticentromere antibody(70.9%,p< 0.001), presenting a similar frequency of peripheral vascular manifestations as the other subsets(p >0.05) (table 1). At the end of follow-up, deaths represented 20.1% of dSSc, 18.1% of vsSSc and 15.8% of limited SSc, with no death in nvsSSc(p< 0.01).  The survival rate in vsSSc was similar to dSSc, but significantly higher than lSSc and nvsSSc (figure 1).

Conclusion: The analysis of the visceral involvement permitted the characterization of two distinct subgroups without skin thickening (vsSSc and nvsSSc) with significant differences in survival. One subset is characterized by predominant visceral involvement (ILD or PAH), and worse prognosis (vsSSc), while the other had a significantly milder disease and higher frequency of anticentromere antibody (nvsSSc).

Table 1

Figure 1

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/impact-of-visceral-involvement-in-the-characterization-and-prognosis-of-patients-without-skin-involvement-classified-as-systemic-sclerosis-ssc-according-to-2013-acr-eular-criteria-in-a-large-single/