How to Choose Core Outcome Measurement Sets for Clinical Trials: OMERACT 11 Approves Filter 2.0

Objective. The Outcome Measures in Rheumatology (OMERACT) initiative works to develop core sets of outcome measures for trials and observational studies in rheumatology. At the OMERACT 11 meeting, substantial time was devoted to discussing a conceptual framework and a proposal for a more explicit working process to develop what we now propose to term core outcome measurement sets, collectively termed "OMERACT Filter 2.0." Methods. Preconference work included a literature review, and discussion of preliminary proposals through face-to-face discussions and Internet-based surveys with people within and outside rheumatology. At the conference, 5 interactive sessions comprising plenary and small-group discussions reflected on the proposals from the viewpoint of previous and ongoing OMERACT work. These considerations were brought together in a final OMERACT presentation seeking consensus agreement for the Filter 2.0 framework. Results. After debate, clarification, and agreed alterations, the final proposal suggested all core sets should contain at least 1 measurement instrument from 3 Core Areas: Death, Life Impact, and Pathophysiological Manifestations, and preferably 1 from the area Resource Use. The process of core set development for a health condition starts by selecting core domains within the areas ("core domain set"). This requires literature searches, involvement (especially of patients), and at least 1 consensus process. Next, developers select at least 1 applicable measurement instrument for each core domain. Applicability refers to the original OMERACT Filter and means that the instrument must be truthful (face, content, and construct validity), discriminative (between situations of interest) and feasible (understandable and with acceptable time and monetary costs). Depending on the quality of the instruments, participants formulate either a preliminary or a final "core outcome measurement set." At final vote, 96% of participants agreed "The proposed overall framework for Filter 2.0 is a suitable basis on which to elaborate a Filter 2.0 Handbook." Conclusion. Within OMERACT, Filter 2.0 has made established working processes more explicit and includes a broadly endorsed conceptual framework for core outcome measurement set development.