Pooled indices to measure rheumatoid arthritis activity: a good reflection of the physician's mind?

Several pooled indices for the assessment of rheumatoid arthritis disease activity are available to rheumatologists. Face and criterion validity of these instruments can be assessed by determining the association of their measurements with opinions of physicians. Several confounding aspects must be considered in such analyses, especially blinding of the person(s) making the decisions to the instruments being studied and to the objective of the study in general. From several studies in the literature, there is currently no evidence that any one of the available composite indices is better or worse than any other. The choice of index in clinical practice should ideally be based on practical considerations related to the needs of the rheumatologist in the respective health care setting.