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 est…