Background The development of radiographic damage over time has been investigated in patients with ankylosing spondylitis, but not yet in early axial spondyloarthritis (axSpA). DESIR is an inception cohort, following patients with inflammatory back pain (IBP) of short duration, and provides an attractive setting to investigate the development of radiographic damage in axSpA. We have recently shown that the modified Stoke in Ankylosing Spondylitis Spine Score (mSASSS) is the most sensitive and adequate scoring method in (early) axSpA.
Objectives To analyse the development and progression of radiographic damage in the spine in patients with IBP and early axSpA.
Methods Patients with IBP for no longer than 3 years and with a clinical suspicion for axSpA were included in the DESIR cohort. Yearly cervical and lumbar radiographs from the first 2 years of follow-up were used in this analysis. Patients with radiographs available allowing the estimation of at least one (1-year or 2-year) progression interval were included in this analysis. Two trained readers independently scored the radiographs according to the mSASSS (0-72). Scores per vertebral corner were averaged between the readers. One-year (baseline-year 1 and year 1-year 2) and two-year (baseline-year 2) progression scores were computed. Progression was assessed in each of the different subgroups of patients definedaccording to the fulfillment of the ASAS axSpA criteria, imaging arm (modified New York Criteria (mNYC) +/- and MRI positivity (according to the ASAS definition)), and clinical arm only (+/- positive CRP) at baseline. In addition, patients were grouped according to presence of baseline syndesmophytes.
Results In total, 608 patients (mean age 36.0 (SD 8.8) years, 47% males, 74% fulfilling ASAS axSpA criteria) were included. At baseline, the average mSASSS was 0.62 (2.74). From these patients, 929 one-year mSASSS progression intervals could be obtained and 441 two-year progression intervals. Patients fulfilling the ASAS axSpA criteria had on average 0.27 (1.57) mSASSS-units progression in 2 years (0.19 (1.16) in the cervical spine and 0.08 (0.63) in the lumbar spine), whereas those not fulfilling the criteria showed a progression of 0.08 (1.03) units. Patients fulfilling the imaging arm had a progression of 0.39 (2.00) mSASSS-units per 2 years. Within this subgroup of patients, patients fulfilling the mNYC and with a negative MRI had the highest progression, followed by those mNYC+ and MRI+ and lastly those mNYC- but with MRI+ (Table). Patients fulfilling only the clinical arm of the ASAS criteria had a progression of 0.11 (0.60) mSASSS-units per 2 years. Patients with baseline syndesmophytes (across all subgroups) had a 2-year progression of 0.78 (2.75) mSASSS-units.
Conclusions Development of spinal radiographic progression can be captured in a cohort of patients with early axSpA within a 2-year follow-up. Progression is higher in patients fulfilling the mNYC and also in patients with baseline syndesmophytes.
Disclosure of Interest None declared