To determine if quantitative assessment of a reduced number of joints provides information equivalent to that obtained by the traditional 60-joint evaluation in detecting changes in patients participating in clinical trials of rheumatoid arthritis (RA).
The changes in quantitative joint scores of patients from 3 previously reported clinical trials were compiled and compared with changes in quantitative scores derived using a reduced number of joints. Effect sizes were calculated (mean change in joint score/standard deviation of joint score) and compared for the different joint indices.
The effect sizes of the joint scores derived using a reduced number of joints were similar to those of the original 60-joint score. The reduced joint count scores revealed significant changes for clinical trials involving as few as 15 patients.
Reduced joint count scores may be used to evaluate the results of clinical trials without decreasing the ability to detect change over time. Quantitative assessment of a reduced number of joints may also facilitate assessment of responses to treatment in the routine care of patients with RA.