Clinically asymptomatic axial disease in psoriatic spondyloarthropathy. A retrospective study

The aim of this study was to analyse retrospectively the prevalence and the clinical features of clinically asymptomatic axial involvement in patients with psoriasis and axial radiological features of spondyloarthropathy (PsSpA). We performed a cross-sectional study based on the clinical records of 70 patients, 44 men and 26 women, with a mean age of 48.7+/-14.2 years. PsSpA was defined by the presence of radiographic sacroiliitis (SI) greater than or equal to grade 2, and/or any other typical radiological sign of spondylitis in patients with psoriasis. When the radiological signs were present in the absence of inflammatory back pain and/or buttock pain, patients were grouped as having asymptomatic axial disease. HLA-B27 was determined by serological methods in the 70 patients and in 82 healthy controls from our general population. Fourteen patients (20%), 11 with radiological SI, two with facet joint erosion-fusion and one with aseptic discitis, showed no evidence of symptomatic spinal disease. Twenty-nine patients (41%) showed cervical spine disease (CSD), but only 17 of them (58.6%) had pain and rigidity at this level, whereas 12 (41.4%) did not show clinical symptoms. CSD was associated with duration of arthritis (P = 0.043) and peripheral erosions (P = 0.037). HLA-B27 correlated well with bilateral SI (P = 0.002) and PsSpA (P<0.0004, RR 6.4), but showed no association with unilateral SI nor with syndesmophytes or asymptomatic disease. Univariate analysis demonstrated associations between symptomatic disease and longer duration of arthritis (P = 0.041) and higher IgM values (P = 0.05). There is a high prevalence of asymptomatic involvement in patients with PsSpA The significance of these asymptomatic changes is not known, but they probably represent a common characteristic of spondyloarthropathies rather than a specific feature associated with psoriasis.