Prevalence and consequences of psoriasis in recent axial spondyloarthritis: an analysis of the DESIR cohort over 6 years.

Objectives: The consequences of psoriasis associated to axial spondyloarthritis (axSpA) are unclear. The objectives were to determine the prevalence and the consequences of psoriasis in recent axSpA over 6 years of follow-up.

Methods: The multicentric prospective cohort DESIR (NCT01648907) of adult patients with recent inflammatory back pain suggestive of axSpA was analysed over 6 years. Psoriasis was recorded at each visit and cumulative prevalence and incidence were calculated. Patients with vs without psoriasis at any time point were compared. Outcomes included disease activity (Ankylosing Spondylitis Disease Activity Score-C reactive protein (ASDAS-CRP), joint and enthesitis count, CRP), patient-reported outcomes for function (Health Assessment Questionnaire for axSpA, HAQ-AS) and quality of life, and treatment use over 6 years. Outcomes were compared through univariable and multivariable analyses, as well as linear mixed effect models.

Results: In 589 patients, mean age 40.5±8.7 years, 45.8% men and baseline mean symptom duration 1.5±0.9 years, the cumulative prevalence of psoriasis increased from 16.8% (99/589) at baseline to 26.8% (158/589) at 6 years, leading to an incidence of 2.1/100 patient-years. Over 6 years of follow-up, patients with psoriasis developed more synovitis (p=0.008), and received more methotrexate (cumulative use, 25.5% vs 11.8%, p<0.001) and biological disease-modifying drugs (55.7% vs 38.5%, p<0.001). There were no significant consequences of psoriasis on other outcomes, including disease activity (ASDAS-CRP), functional capacity (HAQ-AS) and quality of life.

Conclusion: Psoriasis is frequent in early axSpA. AxSpA patients with psoriasis had more swollen joints over time and received more biologics; they did not have worse outcomes related to axSpA in terms of activity and severity.

Trial Registration Number: NCT01648907.