Psoriasis is a heterogeneous skin disease with no reliable cure. However, early diagnosis, prognosis, and understanding the long-term outcomes of the disease may improve care. This study aims to evaluate the clinical course of psoriasis and identify potential indicators of long-term outcomes.

This non interventional inception cohort study included a total of 721 patients with recent-onset psoriasis who were aged 15 years or older. The data for the study was collected from medical records, registers, and questionnaires. The primary outcomes of the study were disease severity, and psoriatic arthritis (PsA) assessed using recursive partitioning and regression models.

At a median follow-up of 9.6 years, the cumulative incidence of severe psoriasis at 12 years from enrollment was 21%. Among 509 patients who were clinically examined after 10 years, 20% with plaque onset and 48% with guttate onset had minimal disease activity without treatment, and 24% had PsA. Recursive partitioning showed that the cumulative incidence of severe disease in patients with the above-median disease was 52% compared with 11% in patients with the below-median disease.

The research concluded that the IL-23 pathway is associated with the clinical course of psoriasis, and patients with the above-median disease are at a high risk of severe disease complications.