Inflammatory and structural changes in vertebral bodies and posterior elements of the spine in axial spondyloarthritis: construct validity, responsiveness and discriminatory ability of the anatomy-based CANDEN scoring system in a randomised placebo-controlled trial

Simon Krabbe; Inge J Sørensen; Bente Jensen; Jakob M Møller; Lone Balding; Ole R Madsen; Robert G W Lambert; Walter P Maksymowych; Susanne J Pedersen; Mikkel Østergaard

doi:10.1136/rmdopen-2017-000624

Inflammatory and structural changes in vertebral bodies and posterior elements of the spine in axial spondyloarthritis: construct validity, responsiveness and discriminatory ability of the anatomy-based CANDEN scoring system in a randomised placebo-controlled trial

RMD Open. 2018 Mar 16;4(1):e000624. doi: 10.1136/rmdopen-2017-000624. eCollection 2018.

Authors

Simon Krabbe^{1

2}, Inge J Sørensen^{1

2}, Bente Jensen³, Jakob M Møller⁴, Lone Balding⁴, Ole R Madsen^{2

5}, Robert G W Lambert⁶, Walter P Maksymowych⁷, Susanne J Pedersen^#^{1

2

5}, Mikkel Østergaard^#^{1

2}

Affiliations

¹ Copenhagen Center for Arthritis Research, Center for Rheumatology and Spine Diseases, Rigshospitalet, Glostrup, Denmark.
² Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
³ Center for Rheumatology and Spine Diseases, Frederiksberg and Bispebjerg Hospitals, Copenhagen, Denmark.
⁴ Department of Radiology, Herlev and Gentofte Hospitals, Herlev, Denmark.
⁵ Center for Rheumatology and Spine Diseases, Herlev and Gentofte Hospitals, Herlev, Denmark.
⁶ Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta, Canada.
⁷ Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.

^# Contributed equally.

Abstract

Background: The Canada-Denmark (CANDEN) definitions of spinal MRI lesions allow a detailed anatomy-based evaluation of inflammatory and structural lesions in vertebral bodies and posterior elements of the spine in patients with axial spondyloarthritis (axSpA). The objective was to examine the reliability, responsiveness and discrimination of scores for spinal inflammation, fat, bone erosion and new bone formation based on the CANDEN system and to describe patterns of inflammatory and structural lesions and their temporal development.

Methods: 49 patients with axSpA from an investigator-initiated, randomised, placebo-controlled trial of adalimumab underwent spinal MRI at weeks 0/6/24/48. MR images were scored according to the CANDEN system and the Spondyloarthritis Research Consortium of Canada (SPARCC) method. Total scores, and various subscores, were created by summing individual lesion scores.

Results: The CANDEN spine inflammation score had high responsiveness, similar to the SPARCC MRI spine index (Guyatt's responsiveness index 1.88 and 1.67, respectively), and discriminated between adalimumab and placebo treatment already at 6 weeks' follow-up (P=0.03). Anterior/posterior corner inflammation subscores showed similar responsiveness. Inter-reader reliability for the CANDEN spine inflammation and fat scores was good to very good for status and change scores (intraclass correlation coefficient (ICC)=0.71-0.92). Reliability for CANDEN new bone formation and erosion scores was good to very good for status scores (ICC=0.61-0.75) but, due to minimal progression, poor for change scores (ICC≤0.40).

Conclusions: The CANDEN spine inflammation score showed good responsiveness, discrimination between active treatment and placebo and reliability. The CANDEN spine structural scores had good cross-sectional reliability, but longer studies are needed to investigate their sensitivity to change.

Trial registration number: NCT01029847; Results.

Keywords: inflammation; magnetic resonance imaging; outcomes research; spondylarthritis.

Associated data

ClinicalTrials.gov/NCT01029847