title: Serial ANCA determinations for monitoring disease activity in patients with ANCA-associated vasculitis: systematic review.
abstract: BACKGROUND
  Antineutrophil cytoplasmic antibodies (ANCAs) are considered by some investigators to be sensitive markers of disease activity and have been suggested to predict relapse and guide therapeutic decisions. Studies using serial ANCA monitoring in patients with ANCA-associated vasculitis (AASV) have yielded controversial results during the last 15 years. To assess the diagnostic value of serial ANCA testing in the follow-up of patients with AASV, we conducted a systematic review of the available literature.
  
  
  METHODS
  Studies were identified by a comprehensive search of the PubMed and BIOSIS+/RRM databases, as well as hand searching. Method quality of all eligible studies was assessed with respect to external and internal validity according to established criteria for diagnostic studies.
  
  
  RESULTS
  Twenty-two studies met our inclusion criteria, including a total of 950 patients. Whereas generalizability was not a major problem, assessment of internal validity showed that only a minority of studies reported the combination of consecutive patient recruitment, prospective data collection, and independent determination of both index and reference tests, considered as the ideal for diagnostic test studies. Quantitative meta-analytic calculations were not conducted because of the presence of considerable method heterogeneity.
  
  
  CONCLUSIONS
  The presence of considerable methodological heterogeneity combined with methodological shortcomings with respect to internal validity in the majority of included studies preclude firm conclusions from the available literature concerning the clinical value of serial ANCA determinations for monitoring the follow-up of patients with AASV.
authors.affiliation: Fifth Department of Medicine, University Hospital Mannheim, Faculty of Clinical Medicine, University of Heidelberg, Mannheim, Germany. rainer.birck@med5.ma.uni-heidelberg.de
authors.forename: Rainer
authors.initials: R
authors.lastname: Birck
authors.forename: Wilhelm H
authors.initials: WH
authors.lastname: Schmitt
authors.forename: Isabelle A
authors.initials: IA
authors.lastname: Kaelsch
authors.forename: Fokko J
authors.initials: FJ
authors.lastname: van der Woude
mesh_terms: D000328:Adult; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood*; D001327:Autoimmune Diseases / Q000097:blood* / Q000276:immunology; D015982:Bias; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012107:Research Design; D014657:Vasculitis / Q000097:blood* / Q000175:diagnosis / Q000276:immunology
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic