Clinical features and outcome of 1054 patients with Systemic Sclerosis: analysis of Reuma.pt/SSc registry.

Background: Systemic sclerosis (SSc) is a rare connective tissue disorder with heterogeneous manifestations and outcomes. Besides differences in disease characteristics among distinct ethnic groups and geographical regions, several questions regarding the impact of the disease and the effectiveness of treatments remain unanswered. To address these questions, the Rheumatic Diseases Portuguese Register (Reuma.pt) launched a specific protocol for the prospective follow-up of SSc patients.

Objectives: To describe the baseline characteristics, disease subsets, treatments used and survival of SSc patients registered in Reuma.pt/SSc.

Methods: Data from adult patients with SSc included in Reuma.pt up to November 2020 were analysed. Demographic features, SSc subsets, fulfilment of classification criteria, main clinical and immunological features, comorbidities, treatments used and survival data were described and compared between diffuse cutaneous (dc) and limited cutaneous (lc) disease subsets. Survival was calculated for patients included in Reuma.pt within the first two years of diagnosis.

Results: In total, 1054 patients were included, 87.5% female, with a mean age at diagnosis of 52.7 +/- 14.8 years. The most common subset was lcSSc (56.3%), followed by dcSSc (17.5%), preclinical SSc (13%), overlap syndrome (9.8%) and SSc sine scleroderma (3.3%). Raynaud's phenomenon (93.4%) and skin thickening (76.9%) were the most frequently observed clinical manifestations. Gastrointestinal (62.8% versus 47.8%), pulmonary (59.5% versus 23%) and cardiac (12.8% versus 6.9%) involvements were significantly more prevalent in dcSSc than lcSSc. Ninety per-cent of patients were Antinuclear antibody positive, 52.5% were Anti-centromere antibody positive and 21% anti-topoisomerase positive, with significant differences between lcSSc and dcSSc. One-third of patients were treated with immunomodulators, 53.6% with vasodilators, 23% with glucocorticoids and 2.3% with biologics. During follow-up, 83 deaths (7.9%) were reported. The overall 1-, 2- and 5-year survivals were 98.0%, 96.8% and 92.6%, respectively, without significant differences between lcSSc and dcSSc.

Conclusion: Reuma.pt/SSc data highlights the importance of registries in improving knowledge about rare and complex diseases, such as SSc. Clinical features of Portuguese SSc patients are similar to those of other populations. In recently diagnosed patients, 5-year survival is over 92%. To the best of our knowledge, this is the first study showing that clinical features of Portuguese SSc are similar to those of other cohorts.