Radiographic hand joint space width assessed by computer is a sensitive measure of change in early rheumatoid arthritis.
OBJECTIVE
To compare changes in the computerized measurement of radiographic hand joint space width (JSW) to changes in modified Sharp scores in a retrospective 2-year study of early rheumatoid arthritis (RA).


METHODS
First and last standard clinical hand radiographs of 245 patients with RA were analyzed blind using purpose-written computer software to measure changes in JSW for proximal interphalangeal (PIP) and metacarpophalangeal (MCP) joints in the 3 middle fingers of each hand. Before measurement, the radiographs were scored independently by 2 radiologists using a modification of Sharp scoring.


RESULTS
The paired changes in JSW (-0.051 +/- 0.005 mm) and Sharp score (+3.81 +/- 0.50) were both significant over the study duration. In measured joints showing an increase in joint space narrowing (JSN) score, 92% had a corresponding reduction in JSW. In patients with an increase in total score, including JSN and erosion scores in fingers and wrists, 84% had a corresponding reduction in mean (PIP + MCP) JSW. Patients with no change in Sharp score (47%) still experienced a significant reduction in measured JSW (-0.027 +/- 0.006 mm). HLA-DR genetic markers of severe disease progression were associated with significantly greater reductions in JSW but not increases in Sharp score. (


METHODS
mean +/- standard error of mean).


CONCLUSIONS
Measured JSW averaged over 6 PIP and 6 MCP joints was a valid and more sensitive measure of change than total Sharp score in this study of early RA.
Angwin
Jane
J
GlaxoSmithKline Research and Development, Stevenage, Hertfordshire, UK. jane.s.angwin@gsk.com
Lloyd
Andrew
A
Heald
Geoff
G
Nepom
Gerald
G
Binks
Michael
M
James
Michael F
MF
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000000981:diagnostic imaging* / Q000235:genetics; D042241:Early Diagnosis; D005260:Female; D005384:Finger Joint / Q000000981:diagnostic imaging*; D020022:Genetic Predisposition to Disease; D015798:HLA-DR1 Antigen / Q000235:genetics; D015804:HLA-DR4 Antigen / Q000235:genetics; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012984:Software; D014955:Wrist Joint / Q000000981:diagnostic imaging*
D015798:HLA-DR1 Antigen; D015804:HLA-DR4 Antigen