The Outcome Measures in Rheumatology (OMERACT) initiative has worked since 1992 to develop, improve and endorse standardized core outcome sets for collecting and reporting data in clinical trials of rheumatic diseases[1,2]. The intent of a core outcome set for each individual disease is to create a uniform approach that facilitates comparison and evidence synthesis of data from different trials for a more complete understanding of the effects of interventions and the body of evidence across trials[3]. Appropriate core outcome sets are essential to ensure that a specific minimum set of outcomes is measured. As such, patients, researchers, healthcare professionals and other key-stakeholders should be involved in the selection and endorsement of the core outcome set to ensure they have a relevant impact on healthcare[4].

An OMERACT core outcome set constitutes two related but partially independent components: The what to measure is known as the core outcome domain set, and the core outcome measurement set describes how to measure each of the core outcome domains, describing the measurement instrument or tools used to measure the core outcome domain[5]. Measurement instruments can take a variety of forms: “The tool can be a single question, a questionnaire, a score obtained through a physical examination, a laboratory measurement, a score obtained through observation of an image, and so on”[6,7]. Thus, endorsed outcome domains (the What to measure) need a corresponding standardized and accurate measurement instrument (the How to measure) for a core outcome set to be complete.

In 2008, the OMERACT Gout Special Interest Group (SIG) proposed core outcome domains for acute (gout flare) and chronic (urate lowering therapy) studies at the OMERACT 8 meeting[8]. They conducted a modified Delphi exercise at OMERACT 9[9] and the core outcome domains for acute and chronic studies in gout were endorsed in 2009[10]. Currently most, but not all the endorsed gout core outcome domains have an endorsed measurement instrument (Fig. 1)[11,12]. The endorsement of instruments for acute studies was at OMERACT 11 (2012)[13]. The patient-reported core outcome domains in chronic gout were endorsed at OMERACT 9 and 10. The core outcome set for acute and chronic studies is nevertheless not completed. For acute studies, the activity limitations domain does not have an endorsed instrument and for chronic studies, flares and tophus burden lack endorsed instruments.

In addition to the work by OMERACT in defining outcome domains and measurement instruments in gout[11] The Gout and Crystal Arthritis Network (G-CAN) have defined definitions of core disease elements in gout[14]. Combined these two key pieces of work provide a powerful mechanism for ensuring reporting of clinical trials is uniform.

Despite the work of OMERACT on defining core outcome domains and core outcome measurement set (the instruments) in rheumatic diseases, the use and reporting of these in trials of rheumatologic diseases has been variable[15,16,17]. We conducted this systematic scoping literature review[18] to evaluate the application of the endorsed core outcome domains and measurement instruments[[10], [11], [12],19] in the clinical setting of gout trials by:

Quantifying the extent to which gout trials are collecting and reporting data in accordance with the OMERACT acute and chronic core outcome domains and core outcome measurement set for gout.

Evaluating the uptake and reporting of the core outcome domains for gout before and after the endorsement of the 2009 OMERACT for acute and chronic studies.