A Comparative Study Of Two Classification Criterias In A Retrospective Cohort Of Juvenile Idiopathic Inflammatory Myopathy

Objective: To evaluate the classification ability of EULAR/ACR criteria and B/P criteria in a retrospective cohort of juvenile idiopathic inflammatory myopathy(JIIM).Methods: 189 children suspected of JIIM treated at Children’s Hospital of Chongqing Medical University in the past 10 years were recruited.The children’s clinical manifestations,laboratory examinations,serological and histopathological data were collected,physician’s diagnosis as gold standard,the sensitivity of the EULAR/ACR and the B/P criteria was calculated.Results: There were 189 children,86 females and 103 males wasincluded.The age of onset was 6 months to 17.7 years(7.0±3.6 years).Among them,140 patients were finally diagnosed as JIIM patients(130JDM(92.9%),ADM 5 Cases(3.6%),JPM 5 cases(3.6%)),49 cases were diagnosed as non-JIIM;the B/P criteria classified 117 patients(83.6%)as possible/definite JIIM,the EULAR/ACR criteria classified 121 Cases(86.4%)as possible/definite JIIM,and there was no statistically significant difference in the consistency test between the two classification standards(κ=0.497,p <0.001);the EULAR/ACR criteria can accurately classify 96 patients of JDM,sensitivity was 71.1%.,the B/P criteria can accurately classify 80 JDM patients with a sensitivity of 59.2%.The consistency between the two criteria is poor(κ=0.366 p<0.001),EULAR/ The ACR criteria is better than the B/P criteria;25 children obtain complete muscle biopsy data,of which 24 cases(96.0%)can be classified according to the B/P criteria,while the EULAR/ACR criteria can only classify 22 of them(88.0%),the sensitivity of the two criteria was compared by Chi-square Fisher’s exact test,and the difference was not statistically significant(P>0.05).Conclusion:The 2017 EULAR/ACR criteria shows higher sensitivity and classification rate in children with JIIM in China,especially in the JDM subgroup classification;in the cases of muscle biopsy,there was no statistical difference in the sensitivity of the two classification criteria.