Dr. Kremer et al reply.

Drs. Pincus, Bergman, and Yazici have raised some concerns about our published article comparing the Clinical Disease Activity Index (CDAI) with simultaneous measures of the Routine Assessment of Patient Index Data 3 (RAPID3).1 We believe our publication has clearly established that the validated CDAI scores provide a fundamentally different evaluation of disease status compared with the RAPID3.