title: Comparison of Disease Activity Score (DAS)28- erythrocyte sedimentation rate and DAS28- C-reactive protein threshold values.
abstract: OBJECTIVE
  To estimate the disease activity score (DAS)28-C-reactive protein (CRP) threshold values that correspond to DAS28-erythrocyte sedimentation rate (ESR) values for remission, low disease activity and high disease activity in patients with rheumatoid arthritis.
  
  
  METHODS
  DAS28 data were analysed using a large observational study (Institute of Rheumatology Rheumatoid Arthritis) database of 6729 patients with rheumatoid arthritis. Firstly, the relationship between the DAS28-ESR and the DAS28-CRP values was analysed. Secondly, the best DAS28-CRP trade-off values for each threshold were calculated using receiver operating characteristic (ROC) curves.
  
  
  RESULTS
  The correlation coefficient of ESR versus CRP was 0.686, whereas that of DAS28-ESR versus DAS28-CRP was 0.946, showing the strong linear relationship between DAS28-ESR and DAS28-CRP values. DAS28-CRP threshold values corresponding to remission, low disease activity and high disease activity were 2.3, 2.7 and 4.1, respectively. The sensitivity and specificity from the ROC curves were gradually reduced as DAS28 values became lower.
  
  
  CONCLUSIONS
  This study showed that DAS28-CRP and DAS28-ESR were well correlated, but the threshold values should be reconsidered. As the results were derived from only Japanese patients, it is essential to compare DAS28-CRP threshold values in people of other ethnic groups.
authors.affiliation: Institute of Rheumatology, Tokyo Women's Medical University, Tokyo 162-0054, Japan. einoue@kde.biglobe.ne.jp
authors.forename: Eisuke
authors.initials: E
authors.lastname: Inoue
authors.forename: Hisashi
authors.initials: H
authors.lastname: Yamanaka
authors.forename: Masako
authors.initials: M
authors.lastname: Hara
authors.forename: Taisuke
authors.initials: T
authors.lastname: Tomatsu
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Kamatani
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000175:diagnosis*; D015415:Biomarkers / Q000097:blood; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000032:analysis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein