Development and testing of new candidate psoriatic arthritis screening questionnaires combining optimal questions from existing tools

Research output: Contribution to journalArticlepeer-review

  • External authors:
  • Laura C. Coates
  • Jessica Walsh
  • Muhammad Haroon
  • Oliver Fitzgerald
  • Tariq Aslam
  • Farida Al Balushi
  • A. D. Burden
  • Esther Burden-Teh
  • Anna R. Caperon
  • Rino Cerio
  • Chandrabhusan Chattopadhyay
  • Mark J D Goodfield
  • Lesley Kay
  • Stephen Kelly
  • Bruce W. Kirkham
  • Christopher R. Lovell
  • Helena Marzo-Ortega
  • Neil McHugh
  • Ruth Murphy
  • Nick J. Reynolds
  • Catherine H. Smith
  • Elizabeth J C Stewart
  • Robin Waxman
  • Hilary E. Wilson
  • Philip S. Helliwell


Objective. Several questionnaires have been developed to screen for psoriatic arthritis (PsA), but head-to-head studies have found limitations. This study aimed to develop new questionnaires encompassing the most discriminative questions from existing instruments. Methods. Data from the CONTEST study, a head-to-head comparison of 3 existing questionnaires, were used to identify items with a Youden index score of ≥0.1. These were combined using 4 approaches: CONTEST (simple additions of questions), CONTESTw (weighting using logistic regression), CONTESTjt (addition of a joint manikin), and CONTESTtree (additional questions identified by classification and regression tree [CART] analysis). These candidate questionnaires were tested in independent data sets. Results. Twelve individual questions with a Youden index score of ≥0.1 were identified, but 4 of these were excluded due to duplication and redundancy. Weighting for 2 of these questions was included in CONTESTw. Receiver operating characteristic (ROC) curve analysis showed that involvement in 6 joint areas on the manikin was predictive of PsA for inclusion in CONTESTjt. CART analysis identified a further 5 questions for inclusion in CONTESTtree. CONTESTtree was not significant on ROC curve analysis and discarded. The other 3 questionnaires were significant in all data sets, although CONTESTw was slightly inferior to the others in the validation data sets. Potential cut points for referral were also discussed. Conclusion. Of 4 candidate questionnaires combining existing discriminatory items to identify PsA in people with psoriasis, 3 were found to be significant on ROC curve analysis. Testing in independent data sets identified 2 questionnaires (CONTEST and CONTESTjt) that should be pursued for further prospective testing. Copyright © 2014 by the American College of Rheumatology.

Bibliographical metadata

Original languageEnglish
Pages (from-to)1410-1416
Number of pages6
JournalArthritis Care & Research
Issue number9
Publication statusPublished - 2014