Incidence and prevalence of psoriatic arthritis in patients with psoriasis stratified by psoriasis disease severity: Retrospective analysis of an electronic health records database in the United States

Background: Among patients in the United States with psoriasis (PsO), limited data exist on the incidence and prevalence of psoriatic arthritis (PsA) based on disease severity. Objective: To assess the incidence, prevalence, and predictors of PsA among patients with PsO stratified by PsO severity using treatment type. Methods: Incidence of PsA per 100 PsO patient-years (PY) and prevalence were assessed using the Optum electronic health records database. Incidence was assessed from PsO diagnosis and 1 year after PsO diagnosis overall and stratified by mutually exclusive treatment classes as a severity surrogate. Results: The overall incidence of PsA was 2.9 (95% CI, 2.9-3.0) events per 100 PY. The incidence (95% CI) by severity surrogate was 2.1 (2.1-2.1), 9.9 (9.5-10.4), and 17.6 (16.9-18.3) events per 100 PY for patients with mild, moderate, and severe PsO as determined by receiving nonsystemics, nonbiologic systemic therapy, and biologics, respectively. When excluding patients diagnosed with PsA 1 year after PsO diagnosis, overall incidence was lower (1.7 [95% CI, 1.6-1.7] events per 100 PY), with similar trends for treatment-severity surrogates. Limitations: Results may not be generalizable to a wider population. Conclusion: The risk of developing PsA increased with disease severity and was highest in patients with the most severe PsO.

Automated summary

The risk of developing PsA increased with disease severity among patients with PsO, and was highest in patients with the most severe PsO.