The validity of pooled outcome measures (indices) in rheumatoid arthritis clinical trials.

No consensus exists on the appropriate (set of) endpoints to be reported in rheumatoid arthritis clinical trials. The traditional endpoints are not comprehensive, show overlap, and are insensitive to change. A single, pooled outcome measure or index may be an alternative. However, such an index must be valid and acceptable. An overview of the existing indices suggests several options are available. To date, practical experience with these indices in trials is limited.