The performance of classification criteria for juvenile spondyloarthropathies

Juvenile spondyloarthropathies (JSpA) are a group of rheumatologic diseases with a disease onset before 16; characterized with enthesitis, lower extremity oligoarthritis, involvement of the axial skeleton and HLA B27 positivity. The diversity of classification criteria along with the phenotype heterogeneity makes the classification of JSpA challenging. The aim of our study was to evaluate the performance of the pre-determined and recently proposed classification criteria for JSpA. The study group consisted of 113 patients with JSpA and 150 patients with juvenile idiopathic arthritis (JIA). Eligible criteria for JSpA were applied to all of the enrolled patients. The analysis of sensitivity, specificity and the kappa index were used to verify the performance of the JSpA criteria. The Amor criteria showed the highest sensitivity (98.2%) while the ASAS criteria for the axial SpA had highest specificity (100%). The sensitivity and specificity of the remaining criteria were: 93.8 and 63.8% for ESSG, 95.6 and 62.7% for Garmisch-Partenkirchen, 91.2 and 75.3% for ASAS criteria for peripheral SpA, respectively. Criteria proposed by our group showed the high sensitivity, specificity and kappa value: 90.3, 90.7, 0.843%, respectively. We suggest that criteria proposed by us could be used in the classification of JSpA. However, neither the pre-determined nor the new criteria are totally adequate and efficacious for the classification and diagnosis of this disease. The evaluation of the validity and reliability of proposed criteria in multicentric studies are mandatory, to increase its utility in routine clinical practice.