ASSESSMENT OF 2 SYSTEMS OF SPONDYLOARTHROPATHY DIAGNOSTIC AND CLASSIFICATION CRITERIA (AMOR AND ESSG) BY A SPANISH MULTICENTER STUDY

Objective. To assess the 2 most recently developed sets of spondylarth ropathy (SpA) diagnostic and classification criteria [Amor and the Eur opean Spondyloarthropathy Study Group (ESSG)] in a survey involving a Spanish population with rheumatic disease. Methods. The survey involve d a cross sectional study of 1549 patients with rheumatic disease, who were examined over a week by 36 expert rheumatologists at 28 Spanish rheumatological centers. The head researcher at each participating cen ter was to diagnose patients as having definite SpA, possible SpA, or as having other rheumatic diseases (definite controls) based on the ph ysician's experience and assessment with no reference to the criteria under study. Results. Overall a total of 218 patients were classified as having definite SpA, 1242 as definite controls and 89 as having pos sible SpA. An analysis of the patients diagnosed as definite showed 90 .8 and 83.5% sensitivity, 96.2 and 95.2% specificity, 80.8 and 75.5% p ositive predictive value, and 98.4 and 97.0% negative predictive value for the Amor and ESSG criteria sets, respectively. Conclusions. Both the Amor and ESSG criteria had excellent intrinsic (sensitivity and sp ecificity) and extrinsic (positive and negative predictive value) perf ormance, with no substantial differences between the 2. The results su pport use of the criteria for classifying SpA in daily rheumatologicaI practice. Although not intended as diagnostic criteria, they make use ful tools for the early identification of initial, atypical, or undiff erentiated forms, which fail to strictly meet the diagnostic criteria of the entities that make up the SpA group.