Use of radiographs to measure outcome in rheumatoid arthritis.

Currently, radiographic analysis of the hands and wrists provides the most practical, useful, and objective biologic endpoint for measurement of outcome in rheumatoid arthritis. Semiquantitative scoring methods for cartilage loss and osseous erosions developed by Sharp (Arthritis Rheum 1971; 14: 706-720) and Larsen (Scand J Rheum 1973; 2: 136-138) have established standards for sensitivity and interobserver reliability. Sharp (Arthritis Rheum 1985; 28: 16-24) has shown that in order to reliably measure change in erosion score, a certain degree of worsening (i.e., progression) must take place. At least one year is necessary, preferably two. Others have shown that rheumatoid arthritis erosions take place and progress early (Years 1 to 3) in most patients, and once destruction is established it may not be possible to adequately assess further change radiographically. Therefore, in order to perform a clinical trial of "disease modifying" agents with radiographic analysis as endpoint, the selections of a proper study population and time interval are most critical. Although it may be difficult to perform, an ideal clinical study for a therapeutic intervention would use patients with rheumatoid arthritis of less than five years' disease duration and perform radiographic analysis at a 24-month minimum interval. The selection of a proper control group may be a near impossibility under these circumstances.