Background To date, published studies suggest that a significant proportion of patients with Psoriatic Arthritis (PsA) present asymptomatic sacroiliitis; that is to say, an inflammatory back pain (IBP) absence. This fact could result in the underdiagnosis of axial involvement in these patients (1).
Objectives To evaluate the prevalence of radiographic sacroiliitis in patients with PsA and to determine its association with clinical, analytical and demographic factors.
Methods A cross-sectional, observational, and unicentre study in which clinical, analytical and demographic data from 359 patients belonging to a PsA monographic consultation were analyzed. All patients met the CASPAR criteria. The presence of sacroiliitis in the sacroiliac x-ray image was used as a dependent variable, formerly evaluated by a trained Rheumatologist. Likewise, independent variables related to arthropathy, cutaneous involvement and sociodemographic characteristics of the patients were used as well. A descriptive analysis and two logistic regressions (univariate and multivariate), were performed to associate radiographic sacroiliitis to different covariates.
Results Out of the 359 patients, 214 (59.6%) were men with a mean time of PsA evolution of 10.05±11.6 years. The x-ray image performed showed sacroiliitis in 127 patients (35.4%). Univariate analysis showed that radiographic sacroiliitis is related (p<0.05) to gender (men), psoriasic paternal family history, IBP, positive HLA-B27 antigen and psoriatic cutaneous involvement greater than 25%. The multivariate analysis showed that radiographic sacroiliitis in these patients is predominantly associated to the presence of IBP, the positive HLA-B27 antigen and gender (men). However, sacroiliitis is not not associated to the onset age of PsA (p>0.05).
Conclusions The prevalence of radiographic sacroiliitis in our population is 35.4%, higher than in other series due to the fact that the sacroiliac x-ray images were performed on all patients, regardless of the clinic. The radiographic sacroiliitis in patients with PsA is related to the presence of IBP, HLA-B27 antigen and gender. However, the time of evolution of arthropathy and the onset age of PsA are not related to sacroiliac radiographic involvement.
Jadon DR, Sengupta R, Nightingale A, et al. Axial Disease in Psoriatic Arthritis study: defining the clinical and radiographic phenotype of psoriatic spondyloarthritis. Ann Rheum Dis 2016;0:1–7.
Disclosure of Interest None declared