title: Leukocyte protein calprotectin and outcome in rheumatoid arthritis. A longitudinal study.
abstract: OBJECTIVE
  To determine if calprotectin is predictive for outcome in patients with rheumatoid arthritis (RA).
  
  
  METHODS
  Fifty six RA in-patients with variable disease duration were prospectively followed for five years. Clinical and laboratory data were collected to assess disease activity. Health Assessment Questionnaire (HAQ) and radiographic scores (of hands and wrists) as described by Larsen were used as outcome measures. Plasma calprotectin levels were determined with ELISA technique.
  
  
  RESULTS
  Significant correlations (r) were found cross-sectionally at follow-up between calprotectin concentration and other known parameters of disease activity and severity: CRP (r = 0.67). investigator's global assessment of disease activity (r = 0.57). Waaler titre (r = 0.50). HAQ score (r = 0.48) and number of swollen joints (r = 0.48). Calprotectin at baseline was not identified as an independent predictor for HAQ or radiographic progression in the multivariate analysis.
  
  
  CONCLUSIONS
  The results confirm calprotectin as a good measure of disease activity and joint inflammation in RA. However, the level of calprotectin at baseline was not predictive for radiographic damage or functional impairment five years later.
authors.affiliation: Department of Rheumatology, Haukeland University Hospital, N-5021 Bergen, Norway. tor.madland@helse-bergen.no
authors.forename: Tor Magne
authors.initials: TM
authors.lastname: Madland
authors.forename: Markus
authors.initials: M
authors.lastname: Hordvik
authors.forename: Hans-Jacob
authors.initials: HJ
authors.lastname: Haga
authors.forename: Roland
authors.initials: R
authors.lastname: Jonsson
authors.forename: Johan G
authors.initials: JG
authors.lastname: Brun
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000473:pathology*; D015415:Biomarkers / Q000032:analysis*; D018450:Disease Progression; D005260:Female; D006801:Humans; D007249:Inflammation; D039841:Leukocyte L1 Antigen Complex / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D039841:Leukocyte L1 Antigen Complex