medwireNews: Disease activity has the strongest impact on disability over time in people with early axial spondyloarthritis (axSpA), study findings indicate.
However, enthesitis and spinal mobility, along with sex, are also “key drivers of disability” and should therefore “be systematically assessed” in these patients, report Pedro Machado (University College London, UK) and co-authors in Arthritis Care & Research.
Machado and team analyzed 5 years of data from 644 patients (mean age 33.6 years, 53% women) from the French DESIR early axSpA cohort. The participants had an average symptom duration of 1.5 years and a mean mSASSS of 0.6 units.
They found that disability, measured using the Ankylosing Spondylitis Health Assessment Questionnaire (HAQ‐AS), was independently associated with disease activity, measured by ASDAS‐CRP (adjusted [adj]B=0.205), enthesitis score (adjB=0.011), spinal mobility according to BASMI (adjB=0.087), and female sex (adjB=0.172). All associations were positive and statistically significant.
Hierarchical modeling indicated that ASDAS‐CRP had the greatest influence on HAQ‐AS, followed by gender, enthesitis score, BASMI, tumor necrosis factor inhibitor treatment, symptom duration, and nonsteroidal anti-inflammatory drug treatment.
The researchers therefore suggest that “[c]omprehensive and multimodal treatment strategies that also address enthesitis and spinal mobility may contribute to decreasing the overall level of disability in early axSpA.”
The hierarchical model also automatically generated ASDAS-CRP cutoffs that could differentiate between groups of patients according to their level of disability, at below 1.3 units for inactive disease, 1.3–2.2 units for low disease activity, 2.3–3.5 units for high disease activity, and above 3.5 units for very high disease activity.
Machado et al note that these cutoffs are almost identical to those previously defined for ASDAS-CRP disease activity states, with the only difference being that the hierarchical model used an ASDAS-CRP cutoff of 2.2 units to separate low from high disease activity, whereas the prespecified cutoff was 2.1.
The authors therefore say: “These findings indicate that the disease activity states defined for ASDAS-CRP also perform well in stratifying patients with different levels of disability, which adds to the validity of the ASDAS-CRP cut-offs.”
They conclude: “ASDAS-CRP cut-offs were able to discriminate between different disability profiles in early axSpA, suggesting that ASDAS-CRP can be used as a surrogate measure of disability.”
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