title: Using the Juvenile Arthritis Disease Activity Score based on erythrocyte sedimentation rate or C-reactive protein level: results from the Portuguese register.
abstract: OBJECTIVE
  Our aims were to evaluate the correlation between Juvenile Arthritis Disease Activity Score 27-joint reduced count (JADAS27) with erythrocyte sedimentation rate (ESR) and JADAS27 with C-reactive protein (CRP) scores and to test the agreement of both scores on classifying each disease activity state. We also aimed at verifying the correlation of the 2 scores across juvenile idiopathic arthritis (JIA) categories and to check the correlation between JADAS27-ESR and clinical JADAS27 (JADAS27 without ESR).
  
  
  METHODS
  A nationwide cohort of patients with JIA registered in the Portuguese Register, Reuma.pt, was studied. JADAS27-CRP was adapted by replacing ESR with CRP level as the inflammatory marker. JADAS27-CRP was calculated similarly to JADAS27-ESR as the simple linear sum of its 4 components. Pearson's correlations and K statistics were used in the analyses.
  
  
  RESULTS
  A total of 358 children had full data to calculate JADAS27; 65.4% were female and the mean ± SD disease duration was 11.8 ± 9.1 years. The correlation coefficient between JADAS27-ESR and JADAS27-CRP was 0.967 (P < 0.0001), although the correlation coefficient between ESR and CRP level was 0.335 (P < 0.0001). The strong correlation between JADAS27-ESR and JADAS27-CRP was maintained when compared within each JIA category. The agreement between JADAS27-ESR and JADAS27-CRP across the 4 activity states was very good, showing 91.1% of the observations in agreement; K = 0.867 (95% confidence interval 0.824-0.91). The correlation between JADAS27 with ESR and JADAS27 without ESR was high (r = 0.97, P < 0.0001).
  
  
  CONCLUSIONS
  JADAS27 based on CRP level correlated closely with JADAS27-ESR across all disease activity states and JIA categories, indicating that both measures can be used in clinical practice. Moreover, the correlation of JADAS27 with and without ESR was also high, suggesting that this tool might be useful even in the absence of laboratorial measures.
authors.affiliation: Instituto de Medicina Molecular and Hospital Egas Moniz, Centro Hospitalar Lisboa Ocidental, Lisbon, Portugal.
authors.forename: Ana F
authors.initials: AF
authors.lastname: Mourão
authors.forename: Maria J
authors.initials: MJ
authors.lastname: Santos
authors.forename: José
authors.initials: J
authors.lastname: Melo-Gomes
authors.forename: Fernando M
authors.initials: FM
authors.lastname: Martins
authors.forename: José A
authors.initials: JA
authors.lastname: Costa
authors.forename: Filipa
authors.initials: F
authors.lastname: Ramos
authors.forename: Iva
authors.initials: I
authors.lastname: Brito
authors.forename: Cátia
authors.initials: C
authors.lastname: Duarte
authors.forename: Ricardo
authors.initials: R
authors.lastname: Figueira
authors.forename: Guilherme
authors.initials: G
authors.lastname: Figueiredo
authors.forename: Carolina
authors.initials: C
authors.lastname: Furtado
authors.forename: Ana
authors.initials: A
authors.lastname: Lopes
authors.forename: Margarida
authors.initials: M
authors.lastname: Oliveira
authors.forename: Ana
authors.initials: A
authors.lastname: Rodrigues
authors.forename: Manuel
authors.initials: M
authors.lastname: Salgado
authors.forename: Miguel
authors.initials: M
authors.lastname: Sousa
authors.forename: Jamie C
authors.initials: JC
authors.lastname: Branco
authors.forename: João E
authors.initials: JE
authors.lastname: Fonseca
authors.forename: Helena
authors.initials: H
authors.lastname: Canhão
mesh_terms: D000293:Adolescent; D001171:Arthritis, Juvenile / Q000097:blood / Q000175:diagnosis* / Q000473:pathology; D015415:Biomarkers / Q000097:blood; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000032:analysis*; D002648:Child; D005260:Female; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood*; D007596:Joints / Q000473:pathology*; D016014:Linear Models; D008297:Male; D011174:Portugal; D011237:Predictive Value of Tests; D011379:Prognosis; D012042:Registries; D015203:Reproducibility of Results; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D018836:Inflammation Mediators; D002097:C-Reactive Protein