Damage Control: Functional Status in Spondyloarthritis

Key points
• Structural damage to the spine and disease activity determine the functional status of patients with early axial spondyloarthritis.

• If early structural damage is slow to develop, disease activity is the primary determinant of functional status in patients with axial spondyloarthritis.

• Unexpectedly, patients with rapid radiographic spinal progression rarely develop clinically symptomatic structural damage early in the course of axial spondyloarthritis.

Background
Significant functional impairment and reduced mobility are common in axial spondyloarthritis. Poddubnyy and colleagues¹ in Germany note that prior studies show a clear connection between structural damage in the spine and impaired functional mobility. However, no studies have examined the effect of structural damage on functional status in patients with early axial spondyloarthritis.

The researchers sought to determine the impact on function that structural damage in the spine has in patients with early axial spondyloarthritis. They recently presented their findings in Rheumatology.

The study
The researchers looked at 210 patients with early axial spondyloarthritis who participated in the German Spondyloarthritis Inception Cohort. Functional status scores were utilized to determine whether disease activity and structural damage were related to function.

The results
• Patients in the ankylosing spondylitis subgroup had higher overall structural damage scores.

• After 2 years, structural damage scores showed an association with functional status.

• Disease activity scores showed a clear association with functional status.

• There was a slightly weaker association between functional status and structural damage than with disease activity, especially early on.

Implications for clinicians
• Counsel patients with axial spondyloarthritis that disease activity is a good predictor of their expected functional ability throughout the disease.

• Targeting low disease activity should also lead to maintained functional status.

• Structural damage becomes more relevant in fast progressors and in patients with advanced disease.

• Frequently, radiographic spinal progression does not mean functional impairment. Clinical correlation should be made.

Disclosures:

The German Federal Ministry of Education and Research, Abbott/Abbvie, Amgen, Centocor, Schering-Plough, and Wyeth provided funding.

References:

1. Poddubnyy D, Listing J, Haibel H, et al. Functional relevance of radiographic spinal progression in axial spondyloarthritis: results from the German Spondyloarthritis Inception cohort. Rheumatology. 2018 Jan 24. doi: 10.1093/rheumatology/kex475.