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CAROL A. WALLACE, ANGELO RAVELLI, BIN HUANG, and EDWARD H. GIANNINI ABSTRACT. Methods. We used the OMERACT filter paradigm to estimate the validity of the criteria within each of the filter's 3 components: truth, discrimination, and feasibility, in 5 categories of JIA: systemic arthritis, persistent and extended oligoarthritis, and rheumatoid factor-positive and negative polyarthritis. Data sources for determining validity estimates included a Delphi questionnaire survey sent to 246 pediatric rheumatologists in 34 countries, a consensus conference attended by 20 senior pediatric rheumatologists representing 9 countries, a retrospective chart review of 437 patients with JIA from 3 tertiary care clinics who had been followed between 4 and 22 years, and the literature. Results. Truth component: face and content validity. These aspects of validity were largely established via the Delphi questionnaire exercise and the consensus conference. Using an 80% consensus level, participants felt that a set of non-redundant variables could effectively differentiate the clinical states of ID, CRM, and CR. Criterion validity could not be irrefutably established because no gold standard for inactive disease exists for JIA. As an alternative, published investigations of remission in JIA were used to estimate concurrent and convergent validity, as surrogates for criterion validity and as indicators of overall construct validity. Correlational analyses revealed the new criteria to have good construct validity. Discrimination component: the criteria demonstrated moderate to high levels of classification, prognosis, and responsiveness (sensitivity to change) using data from the chart review. Patients who were able to attain CR remained disease-free for substantially longer periods than did those who attained only ID or CRM. Responsiveness was evidenced by the ability of the criteria to allow movement of most patients between the disease states, consistent with what is known of the course of the disease. Feasibility component: Results of the Delphi and consensus conference produced a set of criteria that are easily, quickly, and inexpensively completed in the physician's office, and present minimal or no risk to the patient. Conclusion. The preliminary criteria demonstrated moderate to excellent validity characteristics in some, but not all components of the OMERACT filter. Prospective validation studies are under way. (First Release Feb 15, 2006; J Rheumatol 2006;33:789–95)
Key Indexing Terms: JUVENILE IDIOPATHIC ARTHRITIS
From the Division of Immunology, Rheumatology, and Infectious Disease, Children's Hospital and Regional Medical Center; and Department of Pediatrics, University of Washington School of Medicine, Seattle, Washington, USA; the IRCCS G. Gaslini, Pediatria II, Genoa, Italy; and the Center for Epidemiology and Biostatistics, and William S. Rowe Division of Rheumatology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA. Supported by grants from Pfizer Inc., Centocor Inc., the Howe Endowment for JRA Research, and NIAMS P60AR47784. C.A. Wallace, MD, Associate Professor, Division of Immunology, Rheumatology, and Infectious Disease, Children's Hospital and Regional Medical Center, Department of Pediatrics, University of Washington School of Medicine; A. Ravelli, MD, Dirigente Medico, IRCCS G. Gaslini, Pediatria II; B. Huang, PhD, Assistant Professor, Center for Epidemiology and Biostatistics; E.H. Giannini, MSc, DrPH, Professor, William S. Rowe Division of Rheumatology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine. Address reprint requests to Dr. C.A. Wallace, Division of Rheumatology, Children's Hospital and Regional Medical Center, 4800 Sandpoint Way NE, Seattle, WA 98105, USA. E-mail: cwallace@u.washington.edu
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