Objectives: This study aimed to estimate rates of cancer or opportunistic infection in patients with psoriatic arthritis (PsA) compared with patients without PsA.
Methods: Using the Clinical Practice Research Datalink, we conducted a cohort study of patients with a PsA diagnosis and patients without such diagnosis, matched on age, sex, general practice, and calendar time, to assess the incidence of cancers (solid, hematologic, and nonmelanoma skin cancer) and opportunistic infections. We estimated incidence rates (IRs) and IR ratios (IRRs) with 95% confidence intervals (CIs) for each outcome and stratified results in the PsA cohort by receipt of systemic PsA drugs.
Results: The rate of hematologic cancer was slightly higher in the PsA cohort compared with the non-PsA cohort (IRR, 1.52; 95% CI, 1.10-2.10), whereas the rates of solid cancer and of nonmelanoma skin cancer were similar between the PsA and non-PsA cohorts (IRR, 1.01; 95% CI, 0.90-1.13; and IRR, 0.97; 95% CI, 0.82-1.14, respectively). Incidence rates were higher for PsA patients who received prescriptions for PsA drugs compared with those who did not. The IRs for infection were higher in the PsA compared with the non-PsA cohort (IRR, 1.39; 95% CI, 1.31-1.47) and were significantly higher in patients who received prescriptions (IRR, 1.71; 95% CI, 1.52-1.91).
Conclusions: The rates of solid and nonmelanoma skin cancers were similar in patients with PsA compared with patients without PsA, but the rates of hematologic cancer and opportunistic infections were higher in patients with PsA. In patients with PsA, rates of all outcomes were higher among those who received prescriptions for systemic PsA therapy.