Characteristics of Overlap Syndrome in a Large Cohort of Brazilian Patients With Systemic Sclerosis: A Retrospective Analysis

Abstract

Objective: Systemic sclerosis (SSc) often presents alongside other connective tissue disorders, termed "overlap syndrome (OS)." This study aimed to characterize patients with SSc with OS compared to those without OS in a tertiary university hospital in Brazil.

Methods: A retrospective analysis of demographic, clinical, and laboratory data from 787 SSc patients was performed using electronic medical records. Patients were classified based on the 2013 American College of Rheumatology/European Alliance of Associations for Rheumatology criteria for SSc and additional criteria for systemic lupus erythematosus (SLE), idiopathic inflammatory myopathy (IIM), Sjögren disease (SjD), and rheumatoid arthritis (RA). Statistical analysis, including univariate and multivariate methods, identified factors associated with OS.

Results: Ninety-one patients (11.6%) had OS, mainly with SLE (29.7%), SjD (26.4%), RA (24.2%), or IIM (19.8%). Patients with OS were younger, with an earlier age at onset (P = 0.004) and at diagnosis (P = 0.003). They presented a higher prevalence of limited SSc (P _trend = 0.06), musculoskeletal symptoms (P < 0.001), neoplasia (P = 0.03), and sicca symptoms (P < 0.001); and were associated with a lower frequency of pulmonary hypertension (P = 0.048) and comorbidities such as diabetes mellitus (P = 0.02) and dyslipidemia (P = 0.02). A higher prevalence of anti-Ro (P = 0.007) and a lower prevalence of anti-Scl70 (P = 0.003) were also observed. Patients with OS were more frequently prescribed glucocorticoids (GCs; P < 0.001), methotrexate (P = 0.01), and leflunomide (P = 0.001). Multivariate analysis identified limited SSc (odds ratio [OR] 3.1), neoplasia (OR 3.4), and use of GCs (OR 8.2) and leflunomide (OR 5.5) with OS. No worse prognosis was observed.

Conclusion: Overall, Brazilian patients with SSc with OS have distinct clinical characteristics but do not have a worse prognosis compared to those without OS.

Keywords: overlap syndrome; prognosis; systemic sclerosis.