Radiographic progression is usually assessed by Sharp-based methods (van der Heijde-modified Sharp score and the Genant-modified Sharp score). The aim of this study was to evaluate, in a range of randomized controlled trials (RCT), the presence of erosions and joint space narrowing (JSN) in all individual joints, as well as progression in these joints, and to determine if any redundancy exists due to infrequently involved joints.
Four databases of rheumatoid arthritis RCT that were all scored according to van der Heijde's modification of the Sharp score were included in a descriptive analysis.
Irrespective of different readers, different patient populations, and different disease durations per trial, similar patterns emerged. Both erosions and JSN occurred in all sites. Erosions occurred most frequently in the feet, preferentially in 5th metatarsophalangeal joint (MTP-5). JSN occurred most frequently in the wrist. Change from baseline in erosions and JSN followed the pattern of involvement at baseline, so that MTP-5, and to a lesser extent MTP-3 and MTP-4, preferentially showed progression in erosive damage. Joints in the wrist showed highest tendency to worsen over time with respect to JSN.
These data indicate that both erosions and JSN must be assessed for damage, and that a more abbreviated joint count cannot be used for radiographic scoring.