Session Information
Session Type: Abstract Submissions (ACR)
Background/Purpose: Classification criteria for systemic sclerosis (SSc) are being developed. Twenty-three candidate criteria have been identified, but need to be reduced. The objectives of this study were to: 1) develop a SSc-specific instrument for use in a forced-choice study and evaluate its sensibility (comprehensibility, clarity, face and content validity, and feasibility); 2) use forced-choice methods to reduce and weight criteria; and 3) explore the agreement between SSc experts on the probability that cases were classified as SSc.
Methods: A standardized instrument was tested for attributes of sensibility. The instrument was applied to cases of SSc from 20 cohorts covering a range of probabilities that each case had SSc (very likely to not at all). SSc experts rank-ordered cases from 1 (highest probability) to 20 (lowest probability). Experts then reduced and weighted the 23 criteria using forced choice-conjoint analytic methods and subsequently re-ranked the cases. Consistency in both rankings was evaluated using an intraclass correlation coefficient (ICC).
Results: Experts endorsed clarity of the form (83%), comprehensibility of the instructions and response option (100%), face and content validity (100%) and feasibility. Experts identified ‘skin thickening of the fingers and proximal to the metacarpophalangeal joints’ as a sufficient criterion for SSc classification. Other criteria were reduced and weighted (weight in points): skin thickening of the fingers (14-22), finger tip lesions (9-21), finger flexion contractures (16), telangiectasia (10), abnormal nailfold capillaries (10), puffy fingers (5), calcinosis (12), Raynaud’s phenomenon (13), tendon/bursal friction rubs (21), pulmonary fibrosis/pulmonary hypertension (13), renal crisis (11), esophageal dilation (7) and SSc-related antibodies (15). The ICC for agreement across experts was 0.73 (95% CI 0.58, 0.86) and improved to 0.80 (95%CI 0.68, 0.90).
Conclusion: Our SSc-specific instrument for classification has demonstrable sensibility. The number of criteria were reduced by 35% (from 23 to 15) and weighted. The experts had substantial agreement in rank order. The next phase of criteria development will evaluate a threshold. Our methods reflect the rigors of modern psychometric science, and serves as a template for developing classification criteria in other diseases.
Disclosure:
S. R. Johnson,
None;
R. P. Naden,
None;
J. Fransen,
None;
F. H. J. van den Hoogen,
None;
J. E. Pope,
Actelion and Pfizer,
2,
Actelion and Pfizer,
5;
M. Baron,
None;
A. G. Tyndall,
None;
M. Matucci-Cerinic,
None;
D. Khanna on behalf of ACR/EULAR Classification Criteria SSc,
Actelion, BMS, Gilead, Genentech, ISDIN, and United Therapeutics,
2,
Actelion, BMS, Gilead, Genentech, ISDIN, and United Therapeutics,
5,
Actelion, BMS, Gilead, Genentech, ISDIN, and United Therapeutics,
8.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/systemic-sclerosis-classification-criteria-developing-methods-for-multi-criteria-decision-analysis/