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Trials in rheumatoid arthritis: choosing the right outcome measure when minimal disease is achievable
  1. David T Felson1,
  2. Bin Zhang1,
  3. Jeffrey N Siegel2
  1. 1
    Clinical Epidemiology Unit, Boston University School of Medicine, Boston, Massachusetts, USA
  2. 2
    Food and Drug Administration, Silver Springs, Maryland, USA
  1. David T Felson, Room X200, Boston University School of Medicine, 650 Albany Street, Boston, MA 02118, USA; dfelson{at}

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Exciting advances in rheumatoid arthritis therapy have improved the prospects for patients to live for many years with minimal, if any, detectable disease activity. Recent trials have not only provided evidence on specific medications that might be used to improve outcome but also on therapeutic strategies that might optimise that outcome.

Obviously, the elimination of disease activity is the goal of treating patients with rheumatoid arthritis (RA), or any rheumatic disease. The goal of this editorial is not to question this ultimate aim of treatment or to discuss the design of new treatment strategies or the promise of specific treatments. We propose rather a discussion of how best to measure outcomes in RA trials to optimise our likelihood of achieving this aim of low disease activity at a time when low disease activity is an attainable goal for many patients.

Since they are clinically achievable goals, one reasonable approach to trial outcome measurement in RA might be to focus on low disease activity and, as much as possible, on remission or cure. As suggested by a recent editorial, “Successful therapeutic strategies of the next decade will be measured by the percentage of patients able to achieve remission or at least achieve a very low disease activity state and not by how many patients improved by a certain amount”.1 We shall contend that RA trial outcomes should not focus on remission or even low disease activity, but rather on outcomes that optimise the detection of treatment efficacy. This depends not just on the rate of remission (or low disease activity) in the active treatment group, but on the difference in rates between the treatments being compared. If low disease activity is used as a primary endpoint in a trial in which low disease activity is not attained more often with …

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  • Funding: The views presented in this article do not necessarily reflect those of the FDA. Supported by National Institues of Health grant NIH AR47785.

  • Competing interests: None declared.

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