OMERACT: An international initiative to improve outcome measurement in rheumatology

"Clinical trials are only as credible as their endpoints" [1]. OMERACT strives to improve endpoint outcome measurement through a data driven, iterative alignment process as described below. The key characteristics of OMERACT include a commitment to the data-driven interactive development of a majority alignment across relevant stakeholder groups on determining relevant health outcome domains and endorsing valid, responsive, feasible health outcome measures/scales in patients with musculoskeletal conditions.The first conference on rheumatoid arthritis was held in Maastricht, the Netherlands in 1992. The motivation for this were discussions between two of the authors, [MB and PT], comparing the outcomes used in European clinical trials of rheumatoid arthritis with that of North American clinical trials, and noting that they used different endpoints. This made it extremely difficult to compare and combine in meta-analyses. One of the authors had had a good experience with the nominal group technique to build consensus on some controversial issues around developing a patient preference health status measure [2] and thus suggested using this to develop agreement on a core set of outcomes for RA Clinical Trials.The first conference had 3 goals:(1) To attempt to obtain agreement on the minimum number of outcome measures to be included in all RA clinical trials. This was implemented by a preconference questionnaire, presentation of the evidence on their validity, both small group and plenary discussions on their performance in trials and in individual patients, and then by voting using an electronic voting procedure.(2) To review the range of magnitude of differences judged to be clinically important by experienced clinicians and clinical investigators. This was implemented by a baseline questionnaire and rank ordering of a series of clinical trials and individual patient scenarios, using a nominal group technique.(3) To review the extent to which experienced clinicians and