Reliability of three methods of radiologic assessment in patients with rheumatoid arthritis.
OBJECTIVE
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.
Guth
A
A
Department of Radiology, Ambroise Paré Hospital, Boulogne, France.
Coste
J
J
Chagnon
S
S
Lacombe
P
P
Paolaggi
J B
JB
D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000000981:diagnostic imaging*; D005260:Female; D006225:Hand / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography / Q000379:methods / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D014955:Wrist Joint / Q000000981:diagnostic imaging