LAUSR

BACKGROUND Limited data exist on the incidence and prevalence of psoriatic arthritis (PsA) among US patients with psoriasis (PsO) 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 From the Optum electronic health records database, incidence of PsA per 100 PsO patient-years (PY) and prevalence was assessed. 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.