RELIABILITY OF 3 METHODS OF RADIOLOGIC ASSESSMENT IN PATIENTS WITH RHEUMATOID-ARTHRITIS

RATIONALE AND OBJECTIVES. TO assess the intraobserver reliability of three methods used frequently to evaluate joint destruction in rheumatoid arthritis: the Sharp method, the Larsen method, and the carpo:metacarpal ratio. METHODS. One observer analyzed twice within a 6-week interval 71. radiographs from patients with rheumatoid arthritis. Reliability was estimated by intraclass correlation coefficient (R) and by Altman-Bland graphical method. Correlations were examined by the Spearman's coefficient (r). RESULTS. The intraobserver reliability of each method appeared satisfactory with a good result for the Sharp method (R = 0.97). The correlation was strong (r > 0.80) between the results obtained by Sharp's and Larsen's methods and weaker between the results of the two former methods and the carpo: metacarpal ratio. CONCLUSIONS. Sharp's method should be used preferentially in studies evaluating the radiologic changes in rheumatoid arthritis over time, especially in clinical trials. The carpo:metacarpal ratio may be considered as a complementary method, when wrist destruction is of conceptual importance.