The Sharp/van der Heijde method out-performed the Larsen/Scott method on the individual patient level in assessing radiographs in early rheumatoid arthritis.
OBJECTIVE
To test the reliability of two radiologic scoring methods in rheumatoid arthritis (RA)--the Sharp/van der Heijde (SvH) and the Larsen/Scott (LS)--with generalizability analyses.


METHODS
Films of 51 patients representing the spectrum of early RA were read by two raters for each method. The discriminative ability and responsiveness were expressed as: intraclass correlation coefficients (ICCs), two types of smallest detectable difference (SDD), and two types of smallest detectable change (SDC); reflecting measurement error when discriminating between or detecting changes within (1) individuals or (2) groups. They were calculated for (average) scores of one to three raters.


RESULTS
The discriminative capacity (0.85-0.97) and responsiveness (0.91-0.97) were good when expressed by ICC. On the group level the SDDs and SDCs ranged between 0.6-3.3% of the max. obtainable score. On the individual level, the scores showed better reliability measured with the SvH (SDDs 2.0-3.4%) than with the LS (SDDs 5.3-9.2%). The SvH also assessed changes in scores in individuals with less measurement error (SDCs 1.3-2.2%) than the LS (SDCs 2.3-3.9%).


CONCLUSIONS
For early RA patients, the SvH seems preferable if analyses on individual level are included.
Bruynesteyn
Karin
K
Department of Internal Medicine, Division of Rheumatology, University of Maastricht, P.O. Box 5800, 6202 AZ, Maastricht, The Netherlands.
van der Heijde
Désirée
D
Boers
Maarten
M
van der Linden
Sjef
S
Lassere
Marissa
M
van der Vleuten
Cees
C
D000704:Analysis of Variance; D001172:Arthritis, Rheumatoid / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000473:pathology; D001175:Arthrography; D003627:Data Interpretation, Statistical; D018450:Disease Progression; D006801:Humans; D016032:Randomized Controlled Trials as Topic / Q000379:methods; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D016896:Treatment Outcome