CRP and rheumatoid arthritis: A meta-analysis of randomised controlled trials of biologicals or JAK inhibitors in RA also reported increased placebo response rates for ACR20, ACR50 and ACR70 over the last 20 years, which were statistically significant in the case of the more sensitive measures (ie, ACR50 and ACR70).22 The observation that DAS28(CRP) responses were also numerically better than most other endpoints may also be partly explained by study design and physician assessment bias.