title: Performance of a multi-biomarker score measuring rheumatoid arthritis disease activity in the CAMERA tight control study.
abstract: OBJECTIVE
  To evaluate the performance of individual biomarkers and a multi-biomarker disease activity (MBDA) score in the early rheumatoid arthritis (RA) patient population from the computer assisted management in early rheumatoid arthritis (CAMERA) study.
  
  
  METHODS
  Twenty biomarkers were measured in the CAMERA cohort, in which patients were treated with either intensive or conventional methotrexate-based treatment strategies. The MBDA score was calculated using the concentrations of 12 biomarkers (SAA, IL-6, TNF-RI, VEGF-A, MMP-1, YKL-40, MMP-3, EGF, VCAM-1, leptin, resistin and CRP) according to a previously trained algorithm. The performance of the scores was evaluated relative to clinical disease activity assessments. Change in MBDA score over time was assessed by paired Wilcoxon rank sum test. Logistic regression was used to evaluate the ability of disease activity measures to predict radiographic progression.
  
  
  RESULTS
  The MBDA score had a significant correlation with the disease activity score based on 28 joints-C reactive protein (DAS28-CRP) (r=0.72; p<0.001) and an area under the receiver operating characteristic curve for distinguishing remission/low from moderate/high disease activity of 0.86 (p<0.001) using a DAS28-CRP cut-off of 2.7. In multivariate analysis the MBDA score, but not CRP, was an independent predictor of disease activity measures. Additionally, mean (SD) MBDA score decreased from 53 (18) at baseline to 39 (16) at 6 months in response to study therapy (p<0.0001). Neither MBDA score nor clinical variables were predictive of radiographic progression.
  
  
  CONCLUSIONS
  This multi-biomarker test performed well in the assessment of disease activity in RA patients in the CAMERA study. Upon further validation, this test could be used to complement currently available disease activity measures and improve patient care and outcomes.
authors.affiliation: Correspondence to Marije F Bakker, UMC Utrecht, Department of Rheumatology & Clinical Immunology, Utrecht PO BOX 85500, The Netherlands. m.f.bakker-8@umcutrecht.nl
authors.forename: Marije F
authors.initials: MF
authors.lastname: Bakker
authors.forename: Guy
authors.initials: G
authors.lastname: Cavet
authors.forename: Johannes Wg
authors.initials: JW
authors.lastname: Jacobs
authors.forename: Johannes W J
authors.initials: JW
authors.lastname: Bijlsma
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Haney
authors.forename: Yijing
authors.initials: Y
authors.lastname: Shen
authors.forename: Lyndal K
authors.initials: LK
authors.lastname: Hesterberg
authors.forename: Dustin R
authors.initials: DR
authors.lastname: Smith
authors.forename: Michael
authors.initials: M
authors.lastname: Centola
authors.forename: Joel A G
authors.initials: JA
authors.lastname: van Roon
authors.forename: Floris P J G
authors.initials: FP
authors.lastname: Lafeber
authors.forename: Paco M J
authors.initials: PM
authors.lastname: Welsing
mesh_terms: D018501:Antirheumatic Agents / Q000008:administration & dosage*; D019540:Area Under Curve; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D015415:Biomarkers / Q000097:blood*; D018450:Disease Progression; D006801:Humans; D008727:Methotrexate / Q000008:administration & dosage*; D012372:ROC Curve; D011859:Radiography
chemical_list: D018501:Antirheumatic Agents; D015415:Biomarkers; D008727:Methotrexate