title: Thinking outside the box--The associations with cutaneous involvement and autoantibody status in systemic sclerosis are not always what we expect.
abstract: OBJECTIVE
  To describe the clinical characteristics and survival of anti-topoisomerase antibody positive (ATA+) limited cutaneous systemic sclerosis (lcSSc) and anti-centromere antibody positive (ACA+) diffuse cutaneous systemic sclerosis (dcSSc) patients in a large, multicenter SSc cohort.
  
  
  METHODS
  Data from subjects in the Canadian Scleroderma Research Group (CSRG) cohort were extracted. Descriptive statistics were used to summarize the baseline characteristics, including sociodemographic, clinical and serological features of lcSSc and dcSSc, according to ATA+ and ACA+ subsets. Kaplan-Meier analysis was performed to investigate survival by subsets.
  
  
  RESULTS
  Of the 551 subjects included in this study, 52 (9.4%) had ATA+ lcSSc and 91 (16.5%) had ACA+ dcSSc. Demographic and visceral organ involvement (e.g., gastrointestinal symptoms, interstitial lung disease, pulmonary hypertension, and scleroderma renal crisis) was associated with serologic status more so than with skin subset. On the other hand, calcinosis, joint and peripheral vascular manifestations were associated with skin rather than antibody status. Survival was associated with both skin and autoantibody subsets, with ATA + dcSSc associated with the worse survival compared to ATA+ lcSSc (p = 0.0115), ACA+ lcSSc (p = 0.0216) and ACA+ dcSSc (p = 0.0313).
  
  
  CONCLUSIONS
  This study provides evidence that subsetting using antibody markers in addition to extent of skin involvement may predict clinical outcomes better than skin or serology alone in SSc. These findings can inform ongoing efforts to define more robust SSc subsets compared to those based on the extent of skin involvement or serology alone.
authors.affiliation: Faculty of Medicine, McGill University, Jewish General Hospital, Montréal, Québec, Canada.
authors.forename: Neha
authors.initials: N
authors.lastname: Srivastava
authors.affiliation: Faculty of Medicine, McGill University, Jewish General Hospital, Montréal, Québec, Canada; Division of Rheumatology, Jewish General Hospital, Montréal, Québec, Canada; Lady Davis Institute, Jewish General Hospital, Montréal, Québec, Canada. Electronic address: marie.hudson@mcgill.ca.
authors.forename: Marie
authors.initials: M
authors.lastname: Hudson
authors.affiliation: Lady Davis Institute, Jewish General Hospital, Montréal, Québec, Canada.
authors.forename: Solène
authors.initials: S
authors.lastname: Tatibouet
authors.affiliation: Lady Davis Institute, Jewish General Hospital, Montréal, Québec, Canada.
authors.forename: Mianbo
authors.initials: M
authors.lastname: Wang
authors.affiliation: Faculty of Medicine, McGill University, Jewish General Hospital, Montréal, Québec, Canada; Division of Rheumatology, Jewish General Hospital, Montréal, Québec, Canada.
authors.forename: Murray
authors.initials: M
authors.lastname: Baron
authors.affiliation: Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Marvin J
authors.initials: MJ
authors.lastname: Fritzler
mesh_terms: D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D005260:Female; D006801:Humans; D017563:Lung Diseases, Interstitial / Q000150:complications* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D045743:Scleroderma, Diffuse / Q000150:complications* / Q000276:immunology; D012595:Scleroderma, Systemic / Q000150:complications / Q000175:diagnosis* / Q000276:immunology / Q000401:mortality; D012720:Severity of Illness Index; D015996:Survival Rate
chemical_list: D001323:Autoantibodies
keywords: Systemic sclerosis; autoantibodies; subsets