title: First step in the development of an ultrasound joint inflammation score for rheumatoid arthritis using a data-driven approach.
abstract: OBJECTIVE
  To develop and validate candidate sets of joints and tendons for assessment of ultrasound (US) joint inflammation in rheumatoid arthritis (RA).
  
  
  METHODS
  Patients were included in one of two cohorts from 2010 to June 2013: disease-modifying antirheumatic drug naïve early RA or established RA starting/switching biologics. An extensive US examination was performed by experienced sonographers using a validated grey-scale (GSUS) and power Doppler (PDUS) semiquantitative scoring system with scores 0-3 for both GSUS and PDUS in 36 joints and four tendons. We performed factor analysis in the early RA US data and selected candidate joint/tendon sets based on these results. The proportion of information in the total US scores retained in these candidate sets was assessed by R(2) from linear regression analysis. Finally, the candidate sets and previously proposed joint scores were tested in the established RA cohort, and we also evaluated the sensitivity to change with standardised response means.
  
  
  RESULTS
  227 patients with early RA and 212 patients with established RA were included. We identified two candidate sets of joints/tendons: candidate set A consisted of seven joints/two tendons (meatacarpophalangeal 1 (MCP1), MCP2, proximal interphalangeal 3, radiocarpal, elbow, metatarsophalangeal 1 (MTP1), MTP2, tibialis posterior tendon, extensor carpi ulnaris tendon) and set B of nine joints/two tendons (MCP5 and MTP5 added to set A). Unilateral reduced scores retained 78%-85% of the information in total score, while bilateral reduced scores retained 89%-93%, and both sets performed better than previously proposed reduced joint scores, and similar or slightly better regarding sensitivity to change.
  
  
  CONCLUSIONS
  The reduced GSUS and PDUS scores retained most of the information from the total score and performed well in a validation cohort of established RA.
  
  
  BACKGROUND
  NCT01205854, ACTRN12610000284066.
authors.affiliation: Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.
authors.forename: Anna-Birgitte
authors.initials: AB
authors.lastname: Aga
authors.affiliation: Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.
authors.forename: Hilde Berner
authors.initials: HB
authors.lastname: Hammer
authors.affiliation: Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.
authors.forename: Inge Christoffer
authors.initials: IC
authors.lastname: Olsen
authors.affiliation: Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.
authors.forename: Till
authors.initials: T
authors.lastname: Uhlig
authors.affiliation: Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.
authors.forename: Tore K
authors.initials: TK
authors.lastname: Kvien
authors.affiliation: Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Désirée
authors.identifier: http://orcid.org/0000-0002-5781-158X
authors.initials: D
authors.lastname: van der Heijde
authors.affiliation: Department of Rheumatology, Ålesund Hospital, Helse Møre og Romsdal HF, Ålesund, Norway.
authors.forename: Hallvard
authors.initials: H
authors.lastname: Fremstad
authors.affiliation: Department of Rheumatology, Haukeland University Hospital, Helse Bergen HF, Bergen, Norway.
authors.forename: Tor Magne
authors.initials: TM
authors.lastname: Madland
authors.affiliation: Department of Rheumatology, Drammen Hospital, Vestre Viken HF, Drammen, Norway.
authors.forename: Åse Stavland
authors.initials: ÅS
authors.lastname: Lexberg
authors.affiliation: Department of Rheumatology, Martina Hansens Hospital AS, Bærum, Norway.
authors.forename: Hilde
authors.initials: H
authors.lastname: Haukeland
authors.affiliation: Department of Rheumatology, St Olavs Hospital, Trondheim University Hospital, Trondheim, Norway.
authors.forename: Erik
authors.initials: E
authors.lastname: Rødevand
authors.affiliation: Department of Rheumatology, Hospital Østfold HF, Moss, Norway.
authors.forename: Christian
authors.initials: C
authors.lastname: Høili
authors.affiliation: Haugesund Rheumatism HospitalAS, Haugesund, Norway.
authors.forename: Hilde
authors.initials: H
authors.lastname: Stray
authors.affiliation: The Rheumatology Clinic Dovland/Bendvold, Kristiansand, Norway.
authors.forename: Anne Noraas
authors.initials: AN
authors.lastname: Bendvold
authors.affiliation: Department of Rheumatology, Sørlandet Hospital HF, Kristiansand, Norway.
authors.forename: Dag Magnar
authors.initials: DM
authors.lastname: Soldal
authors.affiliation: Department of Rheumatology, University Hospital of North Norway, Tromsø, Norway Institute of Clinical Medicine, University of Tromsø, Tromsø, Norway.
authors.forename: Gunnstein
authors.initials: G
authors.lastname: Bakland
authors.affiliation: Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Lie
authors.affiliation: Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway.
authors.forename: Espen A
authors.initials: EA
authors.lastname: Haavardsholm
mesh_terms: D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000000981:diagnostic imaging* / Q000188:drug therapy; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D007596:Joints / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013710:Tendons / Q000000981:diagnostic imaging; D014463:Ultrasonography; D018608:Ultrasonography, Doppler
chemical_list: D018501:Antirheumatic Agents
keywords: Disease Activity; Rheumatoid Arthritis; Ultrasonography