S. Kessler et al., Assessing the prevalence of hand osteoarthritis in epidemiological studies. The reliability of a radiological hand scale, ANN RHEUM D, 59(4), 2000, pp. 289-292
Objective-The hands are often involved in the osteoarthritic disease proces
s. A radiological grading scale is presented, derived from a published atla
s, to assess the prevalence of hand osteoarthritis (OA) involvement in clin
ical and epidemiological studies and its reproducibility is studied.
Methods-This hand scale is based on the radiological feature "joint space n
arrowing", which represents the macromorphological process of cartilage los
s. Osteophytes and sclerosis are less important unless seen in conjuction w
ith joint space narrowing. Nine individual joints per hand (four proximal i
nterphalangeal joints (PIP), four distal interphalangeal joints (DIP), firs
t carpometacarpal joint (CMC-1)) are scored dichotomously for the presence
of OA. To save time and to increase reliability a severity grading of radio
logical features is not performed. To determine inter-rater and intra-rater
reliability of the individual joints and the presence of OA in two separat
e joint groups (greater than or equal to 2 PIP or DIP and at least one CMC-
1, used to define "generalised OA" in the ongoing Ulm Osteoarthritis Study)
50 pairs of anteroposterior hand radiographs were read by two investigator
s twice within one month. The kappa coefficient was calculated to quantify
the strength of associations.
Results-On average five minutes were needed to score one hand radiograph. B
oth raters were able to reproduce their own readings in all individual join
ts and for the presence of OA in two separate joint groups after one month.
Reliability was highest for the PIP joints (kappa: 0.56-1.00) it was sligh
tly lower for the DIP joints (0.38-0.87), for the CMC-1 joints (0.58-0.69)
and for OA in two separate joint groups (0.54). The values for interrater a
greement were good as well, kappa coefficients ranged from 0.52 to 0.92.
Conclusion-This grading scale was shown to be reliable within and between r
eaders for all the individual joints as well as for the presence of OA in t
wo separate joint groups. Scoring a limited number of joints dichotomously
makes this scale efficient and therefore useful for clinical and epidemiolo
gical trials, when dealing with large patient samples.