Background/Purpose:   Axial involvement in psoriatic arthritis (PsA) is a controversial issue. Lack of unanimity in the definition has led to a wide range of levels of prevalence in the different series published. On the other hand, although radiographic progression in patients with spondylitis is widely known, the different radiographic characteristics of both entities advise against establishing a parallelism between the evolution of the different lesions or the clinical factors which may have an influence on them. Our objectives werw radiographic progression over four years in a group of patients with PsA and axial involvement and relate radiographic damage with clinical and analytical factors.

Methods: Prospective study with patients diagnosed with PsA according to the CASPAR criteria. Axial involvement was defined as the presence of inflammatory back pain along with sacroiliitis and/or syndesmophytes. Patients with less of five years of evolution from the onset of symptoms were included in the study. The radiographic damage was measured with the PASRI method. The difference between both measurements was four years (+ 1 month). The assessment was carried out by two observers (CM et al.). The clinical factors measured were: age, sex, peripheral involvement, smoking , use of NSAIDs (continuous vs. on-demand), biological treatment, measures of activity (BASDAI), function (BASFI) and mobility (BASMI). The following analytical variables were measured: VSG, PCR, B-CrossLaps, P1NP and HLA-B27. From a radiological perspective, the presence of a dorsal or lumbar fracture was also assessed according to the semiquantitative Gennant method.

Results: The study included 45 patients with PsA and axial involvement. The average age of patients was 53.5 years (SD: 12.9), and 31 patients were men. The kappa coefficient between both raters was 0.70. Radiographic progression was higher in men (3.13 vs. 1.14, p=0.04; in the multivariate analysis: p=0.04, OR: 0.61, 95%CI: 0.39-0.98) and in smokers (active and ex-mokers) (3.81 vs. 1.14, p=0.04; in the multivariate analysis: p=0.04, OR: 0.61, 95%CI: 0.48-0.93). Also, the presence of vertebral fracture was associated to patients with a higher radiographic progression (4.85 vs. 1.82; p=0.001; in the multivariate analysis: p=0.008, OR: 0.59, 95%CI: 0.39-0.87). No differences were found regarding the presence of peripheral manifestations (2.32 vs. 3.57, p=0.3), peripheral joints erosions (2.61 vs. 3.1, p=0.4), continuous use of NSAIDs (1.67 vs. 2.91, p=0.3), biological prescription (2.04 vs. 3.72, p=0.3) or HLA-B27 (2.00 vs. 2.79, p=0.5). A correlation was observed between radiographic progression and the initial PASRI score (p=0.001) and between progression and a lower P1NP concentration (p=0.02). Twelve patients did not show radiographic progression. These patients showed lower initial PASRI scores (5.35 vs. 12.6, p=0,001; in the multivariate analysis: p=0.03; OR: 0.73, 95%CI: 0.55-0.98) and a lower P1NP concentration (38.7 vs. 61.1; p=0.006: in the multivariate analysis: p=0.01; OR: 1.05, 95%CI: 1.008-1.096).

Conclusion: As in patients with spondylitis, male gender, smoking and the presence of initial damage were associated to a higher radiographic progression. Also, these patients were associated to a higher rate of vertebral fracture and lower levels of P1NP. Radiographic progression was not associated to inflammatory parameters, peripheral manifestations or to the treatment used. Approximately 25% of the patients did not show radiographic progression.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/progression-of-radiographic-axial-damage-in-patients-with-psoriatic-arthritis-relation-with-clinical-and-analytical-factors/