title: The Relapsing Polychondritis Disease Activity Index: development of a disease activity score for relapsing polychondritis.
abstract: OBJECTIVE
  The rarity of relapsing polychondritis (RP) has hindered the development of standardized tools for clinical assessment. Here, we describe the development of a preliminary score for disease assessing activity in RP, the Relapsing Polychondritis Disease Activity Index (RPDAI).
  
  
  METHODS
  Twenty-seven RP experts participated in an international collaboration. Selection and definition of items for disease activity were established by consensus during a 4-round internet-based Delphi survey. Twenty-six experts assessed the Physician's Global Assessment (PGA) of disease activity on 43 test cases on a 0-100 scale, yielding a total of 1118 PGA ratings. The weight of each item was estimated by multivariate regression models with generalized estimating equation, using PGA as the dependent variable.
  
  
  RESULTS
  Experts decided in consensus that the RPDAI should consider the 28-day period before each RPDAI assessment. Inter-rater reliability assessed by the intra-class correlation coefficient for the 1118 PGA ratings was 0.51 (CI95%: 0.41-0.64). The final RPDAI score comprised 27 items with individual weights ranging from 1 to 24 and a maximum theoretical RPDAI score of 265. Correlation between the RPDAI scores calculated based on the weights derived from the final multivariate model, and the 1118 PGA ratings was good (r=0.56, p<0.0001).
  
  
  CONCLUSIONS
  We have developed the first consensus scoring system to measure disease activity in relapsing polychondritis (see www.RPDAI.org for online scoring). This tool will be valuable for improving the care of patients with this rare disease.
authors: Department of Internal Medicine & French Reference Center for Rare Auto-Immune & Systemic Diseases, AP-HP, Pitié-Salpêtrière Hospital, 47-83 bd de l'Hôpital, 75013 Paris, France. Laurent.arnaud@psl.aphp.fr
authors: Laurent
authors: L
authors: Arnaud
authors: Hervé
authors: H
authors: Devilliers
authors: Stanford L
authors: SL
authors: Peng
authors: Alexis
authors: A
authors: Mathian
authors: Nathalie
authors: N
authors: Costedoat-Chalumeau
authors: Jane
authors: J
authors: Buckner
authors: Lorenzo
authors: L
authors: Dagna
authors: Clement
authors: C
authors: Michet
authors: Aman
authors: A
authors: Sharma
authors: Ricard
authors: R
authors: Cervera
authors: Julien
authors: J
authors: Haroche
authors: Thomas
authors: T
authors: Papo
authors: David
authors: D
authors: D'Cruz
authors: Philippe
authors: P
authors: Arlet
authors: Jochen
authors: J
authors: Zwerina
authors: Alexandre
authors: A
authors: Belot
authors: Noboru
authors: N
authors: Suzuki
authors: Jean-Robert
authors: JR
authors: Harle
authors: Robert
authors: R
authors: Moots
authors: David
authors: D
authors: Jayne
authors: Eric
authors: E
authors: Hachulla
authors: Isabelle
authors: I
authors: Marie
authors: Toshio
authors: T
authors: Tanaka
authors: Robert
authors: R
authors: Lebovics
authors: David
authors: D
authors: Scott
authors: Eugene J
authors: EJ
authors: Kucharz
authors: Martin
authors: M
authors: Birchall
authors: Kok Ooi
authors: KO
authors: Kong
authors: Guy
authors: G
authors: Gorochov
authors: Zahir
authors: Z
authors: Amoura
mesh_terms: D006801:Humans; D011081:Polychondritis, Relapsing / Q000175:diagnosis*; D012720:Severity of Illness Index