Relationship Between Spinal Mobility and Radiographic Damage in Ankylosing Spondylitis and Psoriatic Spondylitis: A Comparative Analysis

VINOD CHANDRAN, FINBAR D. O'SHEA, CATHERINE T. SCHENTAG, ROBERT D. INMAN, and DAFNA D. GLADMAN

ABSTRACT.

Objective. To correlate measures of spinal mobility used in the assessment of spondyloarthritis with radiographic severity, and to compare ankylosing spondylitis (AS) and psoriatic spondylitis (Ps-Sp) in this clinical-radiographic correlation.

Methods. As part of the International SPondyloarthritis Interobserver Reliability Exercise (INSPIRE) study, 20 spondyloarthropathy (SpA) experts met for an examination exercise assessing 19 patients with SpA — 10 with Ps-Sp (9 men, mean age 52 yrs, mean disease duration 17 yrs) and 9 with AS (7 men, mean age 38 yrs, mean disease duration 16 yrs). Spearman correlation with bias correction was used to correlate median values of the spinal measurements obtained in the INSPIRE study with modified Stoke AS spinal score (mSASSS) and Bath AS Radiology Index-spine (BASRI-s) scores calculated by consensus of 2 assessors.

Results. The 2 radiographic measures performed comparably in relation to clinimetrics in the SpA group as a whole. There was very good correlation between mSASSS and the occiput-to-wall distance, tragus-to-wall distance, modified Schober, and lateral spinal flexion in the entire group (r_s > –0.64, p < 0.05 for each measure). There was also good correlation between mSASSS and cervical rotation and chest expansion (r_s = –0.58 and –0.54, p < 0.05, respectively). The clinical-radiographic correlations were comparable in the AS and Ps-Sp, except for cervical rotation, which correlated better with mSASSS in Ps-Sp than in AS.

Conclusion. Our study documents the structure-function correlations in axial SpA and provides evidence supporting application of radiographic and clinical measures used in AS to studies of Ps-Sp. (First Release Nov 15 2007; J Rheumatol 2007;34:2463-5)

Key Indexing Terms:

SPONDYLOARTHROPATHY
RADIOGRAPHY
PSORIATIC ARTHRITIS

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From the University of Toronto Psoriatic Arthritis Clinic, Centre for Prognosis Studies in the Rheumatic Diseases, University Health Network, Toronto Western Hospital, Toronto, Ontario, Canada.

V. Chandran is supported by the Krembil Psoriatic Arthritis Fellowship. F.D. O'Shea is supported by an unrestricted research fellowship award from the Irish Society for Rheumatology and Wyeth Pharmaceuticals. The INSPIRE study was supported by the Spondyloarthritis Research Consortium of Canada NRI grant from The Arthritis Society (Canada), the Krembil Foundation, and unrestricted funds from Abbott Canada, Amgen/Wyeth Canada, Schering Canada, Pfizer Canada, and Wyeth Global.

V. Chandran, DM, Clinical Research Fellow; C.T. Schentag, MSc, Research Associate, University of Toronto Psoriatic Arthritis Clinic, Centre for Prognosis Studies in the Rheumatic Diseases, University Health Network, Toronto Western Hospital; F.D. O'Shea, MB, Clinical Research Fellow, University Health Network, Toronto Western Hospital; R.D. Inman, MD, Professor of Medicine, University of Toronto, Senior Scientist, Toronto Western Research Institute; D.D. Gladman, MD, Professor of Medicine, University of Toronto, Senior Scientist, Toronto Western Research Institute.

V. Chandran and F.D. O'Shea contributed equally to this work.

Address reprint requests to Dr. D. Gladman, Toronto Western Hospital, 399 Bathurst Street, 1E-410B, Toronto, ON, M5T 2S8. E-mail:dafna.gladman@utoronto.ca

Accepted for publication August 9, 2007.

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