[Effect size in clinical studies of patients with rheumatoid arthritis. EULAR guidelines and OMERACT core-sets]

Clinical trials in rheumatology are confronted with new challenges. The pharmaceutical industry must be more efficient in identifying and marketing new drugs, regulatory authorities require additional evidence about the effectiveness of new compounds, and the consumer including physicians require more transparency in the selection and use of appropriate outcomes in clinical trials. These challenges find their common denominator in a further standardization of clinical trials that extends beyond the application of Good Clinical Practice. For years, national and international organizations have developed recommendations for the selection of appropriate outcomes in RA clinical trials. However, these recommendations have rarely been data driven or evidence based. The international informal collaboration Outcome Measures in Rheumatoid Arthritis Clinical Trials (OMERACT) has contributed enormously towards the application of a standardized methodology in the development of recommendations to enhance the quality of research in clinical rheumatology. The scope of this initiative goes now far beyond rheumatoid arthritis and now covers all major rheumatic conditions.