To investigate the validity of the 28-joint count for assessment of joint involvement in patients with rheumatoid arthritis (RA).
Joint involvement as determined by the 28- and the 66/68-joint count was compared using data from 735 prospectively studied RA patients.
The joints included in the 28-joint count were more commonly involved than other joints, and findings from the 28-joint count correlated highly with those from the 66/68-joint count in all analyses.
The 28-joint count is a reliable and valid measure for joint assessment. It is easier to perform than the 66/68-joint count, and it addresses the joints that are critically involved.