Objective: To compare the incidence rates of malignancy among patients with psoriatic arthritis (PsA) and patients with rheumatoid arthritis (RA) in the Consortium of Rheumatology Researchers of North America (CORRONA) registry.
Methods: We analyzed 2,970 patients with PsA (7,133 patient-years of followup) and 19,260 patients with RA (53,864 patient-years of followup). Using a standardized adjudication process, we identified 40 confirmed malignancies in the patients with PsA and 307 confirmed malignancies in those with RA. Incidence rates were calculated per 100 patient-years. Incidence rate ratios were estimated, with adjustment for age, sex, disease duration, body mass index, disease activity, year of enrollment, and medication use.
Results: The overall malignancy incidence per 100 patient-years was similar between patients with PsA and patients with RA (0.56 [95% confidence interval (95% CI) 0.40-0.76] and 0.56 [95% CI 0.50-0.63], respectively). Nonmelanoma skin cancer was the most common type of cancer in the overall cohort, with an incidence rate of 0.21 (95% CI 0.12-0.35) in PsA, and 0.20 (95% CI 0.17-0.24) in RA, with a calculated incidence rate ratio of 1.05 (95% CI 0.61-1.80; P = 0.85). Lymphoma rates were similar in PsA and RA (0.04 [95% CI 0.01-0.12] and 0.04 [95% CI 0.02-0.06], respectively; incidence rate ratio 1.00 [95% CI 0.17-3.11]; P = 0.67). The adjusted incidence rate ratio of malignancy in PsA versus RA was 1.17 (95% CI 0.82-1.69; P = 0.37).
Conclusion: The incidence rates across malignancy subtypes were similar in the PsA and RA cohorts from a US registry.
Copyright © 2014 by the American College of Rheumatology.