Comparison of disease activity measures for anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis
- P A Merkel1,
- D D Cuthbertson2,
- B Hellmich3,
- G S Hoffman4,
- D R W Jayne5,
- C G M Kallenberg6,
- J P Krischer2,
- R Luqmani7,
- A D Mahr8,
- E L Matteson9,
- U Specks9,
- J H Stone,
- for the Vasculitis Clinical Research Consortium10
- 1Boston University School of Medicine, Boston, Massachussets, USA
- 2University of South Florida, Tampa, Florida, USA
- 3Kreiskrankenhaus Plochingen, Plochingen, Germany
- 4Cleveland Clinic, Cleveland, Ohio, USA
- 5Addenbrookes Hospital, Cambridge, UK
- 6University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
- 7University of Oxford, Oxford, UK
- 8Hospital Cochin, Paris, France
- 9Mayo Clinic, Rochester, Minnesota, USA
- 10Massachusetts General Hospital, Boston, Massachussets, USA
- P A Merkel, Vasculitis Center, E5, Boston University School of Medicine, 72 East Concord Street, Boston, Massachussets, 02118, USA;
- Accepted 21 July 2008
- Published Online First 29 July 2008
Aim: Currently, several different instruments are used to measure disease activity and extent in clinical trials of anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis, leading to division among investigative groups and difficulty comparing study results. An exercise comparing six different vasculitis instruments was performed.
Methods: A total of 10 experienced vasculitis investigators from 5 countries scored 20 cases in the literature of Wegener granulomatosis or microscopic polyangiitis using 6 disease assessment tools: the Birmingham Vasculitis Activity Score (BVAS), The BVAS for Wegener granulomatosis (BVAS/WG), BVAS 2003, a Physician Global Assessment (PGA), the Disease Extent Index (DEI) and the Five Factor Score (FFS). Five cases were rescored by all raters.
Results: Reliability of the measures was extremely high (intraclass correlations for the six measures all = 0.98). Within each instrument, there were no significant differences or outliers among the scores from the 10 investigators. Test/retest reliability was high for each measure: range = 0.77 to 0.95. The scores of the five acute activity measures correlated extremely well with one another.
Conclusions: Currently available tools for measuring disease extent and activity in ANCA-associated vasculitis are highly correlated and reliable. These results provide investigators with confidence to compare different clinical trial data and helps form common ground as international research groups develop new, improved and universally accepted vasculitis disease assessment instruments.
Competing interests: None declared.
Funding: Grants were received from the National Institutes of Health/National Institute of Arthritis and Musculoskeletal and Skin Diseases (UO1 AR51874) and the National Center for Research Resources/NIH: U54 RR01949703. The Vasculitis Clinical Research Consortium is part of the NIH Rare Diseases Clinical Research Network (http://www.rarediseasesnetwork.org/vcrc). PAM, ELM and JHS were supported by Mid-Career Development Awards in Clinical Investigation (NIH-NIAMS: K24 AR02224, AR047578 and AR049185). None of the funding sources for this study had any role in any aspect of conducting this research, drafting the manuscript, or the decision to publish the data.