International spondyloarthritis interobserver reliability exercise--the INSPIRE study: I. Assessment of spinal measures.
OBJECTIVE
To determine whether the axial measures used in primary ankylosing spondylitis (AS) were reproducible for both AS and psoriatic arthritis (PsA) with axial disease.


METHODS
A group of 20 rheumatologists from 11 countries with expertise in spondyloarthritis (SpA) met for a combined physical examination exercise to assess 10 patients with PsA with axial involvement (9 men, 1 woman, mean age 52 yrs, mean disease duration 17 yrs) and 9 AS patients (7 men, 2 women, mean age 38 yrs, mean disease duration 16 yrs). A modified Latin-square design was used. Measures included were occiput to wall, tragus to wall, cervical rotation, chest expansion, lateral spinal bending, modified Schober, and hip mobility. Data were analyzed using intraclass correlation coefficients (ICC) adjusted for order of measurements.


RESULTS
The majority of the variance was contributed by the patients. There was no order effect. Observer effect was noted especially for chest expansion for both AS and PsA patients, and for the modified Schober in PsA. The ICC demonstrated very good to excellent agreement for most measures for both AS and PsA. Chest expansion provided only moderate agreement for AS and PsA.


CONCLUSIONS
Overall, measures of spinal mobility used in primary AS perform well with respect to interobserver reliability, and are equally reproducible when applied to PsA patients with axial involvement. Thus, these measures should now be evaluated in therapeutic trials of patients with PsA to determine sensitivity to change and concordance with other measures of structural damage.
Gladman
Dafna D
DD
Division of Rheumatology, University of Toronto, Toronto, Ontario, Canada. dafna.gladman@utoronto.ca
Inman
Robert D
RD
Cook
Richard J
RJ
van der Heijde
Desirée
D
Landewé
Robert B M
RB
Braun
Jurgen
J
Davis
John C
JC
Mease
Philip
P
Brandt
Joachim
J
Vargas
Ruben Burgos
RB
Chandran
Vinod
V
Helliwell
Philip
P
Kavanaugh
Arthur
A
O'Shea
Finbar D
FD
Khan
Muhammad A
MA
Pipitone
Nicolo
N
Rahman
Proton
P
Reveille
John D
JD
Stone
Millicent A
MA
Taylor
William
W
Veale
Douglas J
DJ
Maksymowych
Walter P
WP
D000328:Adult; D015535:Arthritis, Psoriatic / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D016059:Range of Motion, Articular / Q000502:physiology*; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013131:Spine / Q000503:physiopathology*; D025241:Spondylarthritis / Q000503:physiopathology*; D013167:Spondylitis, Ankylosing / Q000503:physiopathology