Abstract
Objective We aimed to explore the prevalence of degenerative disc disease (DDD) in psoriatic arthritis (PsA) patients younger than 50 and describe the factors associated with its development. We also examined the association between radiographic axial imaging findings and inflammatory back pain (IBP) and mechanical back pain (MBP).
Methods We included patients with PsA under age 50 who were followed at our prospective observational cohort. We defined DDD as intervertebral disc space narrowing, spur formation, facet joint arthrosis, and spondylolisthesis on anteroposterior and lateral plain radiographs of the cervical and thoracolumbar spine. To identify factors associated with the development of DDD, we used multivariate Cox regression analysis. We used generalized estimating equations (GEE) to test the association between imaging findings (isolated DDD, isolated axial disease, and mixed features) and the type of back pain.
Results Of 814 patients included in the study, 316 (38.8%) were observed to have DDD on plain radiographs of the spine. Factors associated with the development of DDD included older age (HR 1.08, p<0.01), male sex (HR 1.52, p=0.03), diabetes mellitus (HR 2.35, p=0.045), and IBP (HR 2.03, p<0.01). Being employed (vs. unemployed), higher BMI, calcaneal spurs, and targeted DMARD use showed a trending association with DDD. In the GEE analysis, none of the abnormal imaging findings were significantly associated with back pain or IBP.
Conclusion DDD is common in young PsA patients, and its development may be associated with demographic features, comorbidities, and disease-related factors. IBP does not reliably distinguish between axial PsA and DDD.
