Effect of biologic use on the development of psoriatic arthritis: A population-based study

Psoriasis is a chronic inflammatory skin disorder that often precedes psoriatic arthritis. Conflicting evidence exists regarding whether biologic therapies for psoriasis can prevent or delay psoriatic arthritis onset.

To determine whether biologic therapy for psoriasis is associated with a reduced incidence of psoriatic arthritis.

A retrospective cohort study was performed utilizing Optum's de-identified Clinformatics® Data Mart Database, from January 1, 2007, to February 29, 2024. Patients with moderate-to-severe psoriasis were identified by phototherapy use. Among these, some continued on phototherapy, and others switched to a biologic. Individuals with a psoriatic arthritis diagnosis or history of biologic therapy prior to phototherapy initiation were excluded. Cases of psoriatic arthritis developing within 1 year after biologic initiation were also excluded to minimize protopathic bias. Outcomes included the incidence of psoriatic arthritis, measured as incident cases per 1000 person-years. Hazard ratios (HRs) for psoriatic arthritis development were calculated using a multivariable Cox proportional hazards model.

Of 36,508 patients who received phototherapy for psoriasis, 26,470 met eligibility criteria. Among these, 2611 patients switched to biologics, while 23,859 patients did not. The overall PsA incidence rate was 7.85 per 1000 person-years. Patients continuing phototherapy alone had an incidence rate of 8.06 per 1000 person-years, compared with 6.75 in the biologic cohort. After multivariable adjustment for demographics, comorbidities, insurance type and oral systemic therapy, biologic use was associated with a lower likelihood of psoriatic arthritis development compared with phototherapy (adjusted HR, 0.66; 95% CI, 0.53-0.83; p < 0.05).

In this study of moderate-to-severe psoriasis patients, those who initiated biologic therapy demonstrated a lower incidence of psoriatic arthritis than those continuing on phototherapy alone. This suggests that biologic treatments may delay or prevent psoriatic arthritis in psoriasis patients.