An explosion of new agents for chronic and acute gout has highlighted problems with standardized and relevant outcomes for clinical trials and observational studies. Some progress has been made through the OMERACT process, identifying important domains for chronic and acute gout settings and instruments for measuring many of those domains. However, important deficiencies remain. In particular, patient involvement has been relatively limited and probably suggests that not all concerns of patients are captured through the existing OMERACT domains. It is suggested that the framework of the Inter- national Classification of Functioning, Health and Disability be used to guide further work in this area. There are early indications of a valid composite measure of disease activity that might be useful in defining disease states such as remission, low disease activity or patient acceptable state. More work needs to be done on how to best use flares as in- dicators of outcome in chronic gout and how to measure disability during gout flares. Finally, a way to show that serum urate is a good surrogate for relevant and patient- centred outcomes needs to be identified. It seems obvious in clinical practice but is yet to be clearly demonstrated.

We describe the process of patient involvement and the impact of including the patient perspective in OMERACT conferences. OMERACT has taken on a leading role in including patients as research partners in conferences and scientific projects, and this has lead to a formal assessment of the patient perspective over the last 10 years. The role of patients has evolved from a single focus group in 2002 to full integration in all parts of the conference in 2012. Long-term engagement of patient partners has made a significant change in the scope and conduct of rheumatology research. It has enriched the research agenda by identifying previously neglected outcome domains such as fatigue, sleep disturbances and flares, and it has contributed to more patient relevant outcomes in clinical trials. Facili- tating factors toward patient involvement have been the strong commitment of the lead- ership; an adequate selection procedure; an inclusive conference design; an interactive and encouraging moderation style, and self-organized support. However, challenges for the future include where to set the limits for patient partnership, and the representativeness of the patient research partners in particular in terms of country of origin and culture.

The wide spectrum of manifestations of psoriatic arthritis (PsA) makes the standardized assessment of the disease difficult. Outcome measures used in clinical trials so far have been borrowed from that used in rheumatoid arthritis. These measures, such as the EULAR response criteria have been shown to perform well in psoriatic peripheral polyarthritis. These measures may however not perform well in PsA presenting predominantly as oli- goarthritis, axial arthritis, enthesitis or dactylitis. The Group for Research and Assessment of Psoriasis and PsA along with OMERACT has been actively working towards developing validated and feasible measures for the assessment PsA. The first outcome measures workshop in PsA was held at OMERACT 7, and consensus on core domain set for PsA was obtained at OMERACT 8. Subsequently, a few composite indices for the assessment of PsA have been developed and need validation. This article reviews the challenges inherent in the assessment of PsA, the work done by OMERACT and GRAPPA to date, and the future research agenda.

Traditional treatment with conventional Disease Modifying Anti-Rheumatic Drugs (DMARDs) for Rheumatoid Arthritis (RA) aim to suppress inflammation, relieve symptoms and retard joint destruction. Because of the limited efficacy and high risk of toxicity of current treatments, better treatments are needed. For assessing therapeutic efficacy and safety of any new treatment, clinical trials remain the gold standard. In clinical trials, outcome measures are the key tools that allow the impact of any intervention be assessed and compared. Before 1990, RA clinical trials often included 10 or more measures of disease activity. Over the past 20 years, OMERACT has played a critical role in driving global consensus on the development and validation of outcome measures in RA. The RA core data set includes 7 ώ 1 domains (pain, patient global assessment, physical disability, swollen joints, tender joints, acute phase reactants, physician/assessor global assessment, radiographs of joints), which should be assessed in all RA clinical trials. ACR Response Criteria, DAS28 and EULAR Response Criteria are the composite measures used in RA clinical trials globally. Fatigue was added to core data set after OMERACT 8 meeting with a major input from RA patients. OMERACT RA flare group is currently working on developing definition of RA flare. The RA core data set and response criteria had a fundamental impact on clinical trials, and are accepted by regulatory authorities in the licensing of new med- ications. They have become the global standard and used consistently in all clinical trials enabling pooling and comparing different clinical trials to facilitate evidence based practice.

Imaging of the axial skeleton is important for the assessment and classification of patients with axial Spondyloarthritis (axSpA). While magnetic resonance imaging (MRI) is useful to assess the inflammatory and post-inflammatory lesions of these patients, the gold stan- dard for imaging of the structural changes, such as syndesmophytes, is conventional ra- diographs (CR). Very recent data indicate that the parallel occurrence of active inflammatory changes (bone marrow edema) and chronic post-inflammatory (fatty degeneration) lesions have prognostic significance for future radiographic progression in axSpA. Scoring tools for spinal inflammation such as the ASspiMRI-a have been success- fully used in several large clinical trials. A comparison of all scoring methods in a multi- reader experiment has shown that none has preferred particular preference based on OMERACT principles. Quantification of structural spinal changes in ankylosing spondylitis (AS) is performed by evaluation of lateral cervical and lumbar radiographs using the mSASS Score, which is a reliable scoring method for patients who are being followed up for a period of no less than 2 years. A disadvantage of the mSASSS is that the thoracic spine is not included in that system because of technical reasons, even though MRI studies have shown that the lower half of the thoracic spine is most frequently affected in AS. A new scoring system, the RASSS, that concentrates only on bone formation and also includes the lower part of the thoracic spine, is currently under evaluation. This overview on the current knowledge on imaging in axSpA highlights the use of imaging techniques for assessment of clinical outcomes and use in clinical trials.

The assessment of patients with systemic lupus erythematosus (SLE) is very challenging because of the multifaceted nature of the clinical presentations, complexity of the symp- toms and their variation over time. Outcome Measures in Rheumatology (OMERACT) rec- ommended the assessment of disease activity, chronic damage resulting from lupus activity or its treatment, adverse events of drugs, health-related quality of life and eco- nomic impact. The use of instruments is essential for a standardized assessment of the disease domains. For this purpose, several instruments have been developed and vali- dated, and have been used in clinical settings and research. Here, we review these in- struments and provide an update on the recent developments in the field.

To improve the management of the disease and to help patients to a better outcome, it is important to understand the pathological mechanisms behind systemic sclerosis. Also intensive clinical and translational research is needed followed by implementation of the evidence. Systemic sclerosis is a rare heterogenic condition with different pathogenic mechanisms and with different organs being involved. In order to make progress appro- priate measures of the different disease aspects have to be developed. We overview the currently available validated instruments for systemic sclerosis that are supported by the OMERACT filter. The different aspects of their validation in this dis- ease are discussed as well as their feasibility. Many instruments still have shortcomings in validity or are to invasive to be regularly used; many domains of the disease still need proper evaluation instruments. Global disease activity and severity instruments as well as treatment response scales are awaiting full validation to assure optimal clinical research in the future. Appropriate evaluation instruments are essential in clinical research not only to mea- sure current disease state but also to determine prognosis and predict organ damage and eventual premature mortality. They should also deal with patient-specific aspects as coping, illness perceptions, self-esteem etc. in a chronic disease as scleroderma. Once established they will definitely contribute to optimal daily care of patients. This is only achievable with the collaboration of different experts and with the set-up of large patient cohorts of scleroderma in different countries that are followed prospectively and make appropriate validation possible.

The primary systemic vasculitides are complex multisystem disorder where accurate assessment of disease activity and disease damage is difficult. In order to evaluate thera- pies in clinical trials good outcome measures are necessary. In ANCA associated vasculitis (AAV), clinical checklists such as the BVAS are used to measure disease activity and the VDI to measure disease and treatment related damage. These tools were developed by consensus expert opinion; have been used for over a decade in clinical trials and are now well-validated and accepted measures. The availability of good outcome measure was a key factor in enabling therapeutic trials in AAV. OMERACT has endorsed a 'core set' of domains for trials in AAV with validated measures in each domain. In contrast, there has been an absence of outcome measures in large vessel vasculitis and as a consequence almost no clinical trials in giant cell arteritis or Takayasu's arteritis to date. The landscape may be changing with improved imaging techniques and the recent development of the Indian Takayasu's Arteritis Activity Score (ITAS2010). OMERACT has a working group to try and develop and validate outcome measures for large vessel vasculitis, which provides an opportunity for interested researchers to be involved in this process.