Authors’ Reply: Comments on the 2019 Update of the American College of Rheumatology Recommended Rheumatoid Arthritis Disease Activity Measures

We thank Dr. Fleischmann for his comments on the working group's recommendations on rheumatoid arthritis (RA) disease activity measures. While several studies have shown that DAS28-CRP may underestimate disease activity compared to DAS28-ESR (1-4), there also exists conflicting evidence that the two scores have good agreement (5, 6). More stringent cut-offs for DAS28-CRP have been proposed by both Inoue and Fleischmann to improve agreement with DAS28-ESR disease activity categorization, although the thresholds proposed by the two authors differ somewhat (Table 1). Providers, or those designing clinical trials, may choose to use these more stringent DAS28-CRP cut-offs. However, substituting alternative thresholds is premature at this time as only limited validation of these alternate cut-offs has been completed to date (7).