Validation of potential classification criteria for systemic sclerosis

Sindhu R. Johnson*, Jaap Fransen, Dinesh Khanna, Murray Baron, Frank Van Den Hoogen, Thomas A. Medsger, Christine A. Peschken, Patricia E. Carreira, Gabriela Riemekasten, Alan Tyndall, Marco Matucci-Cerinic, Janet E. Pope

*Corresponding author for this work
70 Citations (Scopus)


Objective. Classification criteria for systemic sclerosis (SSc; scleroderma) are being updated jointly by the American College of Rheumatology and European League Against Rheumatism. Potential items for classification were reduced to 23 using Delphi and nominal group techniques. We evaluated the face, discriminant, and construct validity of the items to be further studied as potential criteria. Methods. Face validity was evaluated using the frequency of items in patients sampled from the Canadian Scleroderma Research Group, 1000 Faces of Lupus, and the Pittsburgh, Toronto, Madrid, and Berlin connective tissue disease (CTD) databases. Patients with SSc (n = 783) were compared to 1,071 patients with diseases similar to SSc (mimickers): systemic lupus erythematosus (n = 499), myositis (n = 171), Sjögren's syndrome (n = 95), Raynaud's phenomenon (RP; n = 228), mixed CTD (n = 29), and idiopathic pulmonary arterial hypertension (PAH; n = 49). Discriminant validity was evaluated using odds ratios (ORs). For construct validity, empirical ranking was compared to expert ranking. Results. Compared to mimickers, patients with SSc were more likely to have skin thickening (OR 427); telangiectasias (OR 91); anti-RNA polymerase III antibody (OR 75); puffy fingers (OR 35); finger flexion contractures (OR 29); tendon/ bursal friction rubs (OR 27); anti-topoisomerase I antibody (OR 25); RP (OR 24); fingertip ulcers/pitting scars (OR 19); anticentromere antibody (OR 14); abnormal nailfold capillaries (OR 10); gastroesophageal reflux disease symptoms (OR 8); antinuclear antibody, calcinosis, dysphagia, and esophageal dilation (all OR 6); interstitial lung disease/pulmonary fibrosis (OR 5); and anti-PM-Scl antibody (OR 2). Reduced carbon monoxide diffusing capacity, PAH, and reduced forced vital capacity had ORs of <2. Renal crisis and digital pulp loss/acroosteolysis did not occur in SSc mimickers (OR not estimated). Empirical and expert ranking were correlated (Spearman's ρ = 0.53, P = 0.01). Conclusion. The candidate items have good face, discriminant, and construct validity. Further item reduction will be evaluated in prospective SSc and mimicker cases.

Original languageEnglish
JournalArthritis Care and Research
Issue number3
Pages (from-to)358-367
Number of pages10
Publication statusPublished - 03.2012

Research Areas and Centers

  • Academic Focus: Center for Infection and Inflammation Research (ZIEL)


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