Background/Purpose:

Many systemic treatments for psoriatic arthritis and psoriasis (PsA/PsO) are immune-modulating, which may increase the risk of non-melanoma skin cancer (NMSC).  However, the comparative risks of NMSC are unclear. This study aimed to determine if the risks of NMSC associated with biologic and non-biologic treatments for PsA/PsO differ in their NMSC risk.

Methods:  

Using data from 2006-2011 for 100% of patients with patients with PsA and PsO, we defined separate PsA and PsO cohorts based upon >=1rheumatologist visit for PsA or >= 1 dermatologist visit for PsO, followed by a prescription or administration of etanercept (ETA), adalimumab (ADA), ustekinumab (UST), methotrexate (MTX), cyclosporine (CIC) or ultraviolet light therapy (UV). Patients could be in both cohorts if they meet criteria for each cohort. We identified new treatment episodes, defined specific to each drug as no use of that therapy in the prior 6 month ‘baseline’ period. Eligible subjects were continuously enrolled in Medicare Parts A, B and D in baseline and throughout follow-up. Patients contributing treatment episodes with history of organ transplantation, infection with human immunodeficiency virus, advanced kidney (hemodialysis-dependent), severe liver disease, or cancer diagnoses were excluded. Follow up started from drug initiation date and ended at the earliest date of: NMSC, a 90 day gap in current exposure, death, loss of Medicare coverage or Dec 31, 2011. We identified NMSC using validated claims-based algorithm with a list of physician diagnosis (ICD9 713.x) and procedure codes and calculated the incidence rate (IR) of NMSC for each treatment. Using pairwise propensity scores (PS), we compared NMSC risks between different treatments during follow-up using Cox regression adjusting for PS quintile.

Results:

We identified 10,261 PsA and 31,052 PsO new treatments episodes. For the PsA cohort, 50% of treatment-episode exposure time was in common with the PsO, and 20% of PsO exposure time was in common with PsA exposures. During follow up, patients in the PsA cohort experienced 51 (ADA), 11 (CIC), 31 (ETA), 117 (MTX), <11 (UV) NMSCs, and the PsO cohort experienced 130 (ADA), 106 (CIC), 122 (ETA), 394 (MTX), 273 (UV) NMSCs. The overall IR in PsA was 23.2/1000, ranging from a low of 14.0 (ETA) to a high of 48.9 (CIC). The overall IR in the PsO cohort was 36.3/1000, ranging from 22.4 (ETA) to 53.6 (CIC).  After PS quintile adjustment, significant associations with NMSC were observed for ADA compared to ETA (PsA, Hazard ratio (HR): 1.58, 95% confidence interval (CI): 1.01-2.51; PsO, HR: 1.33 95% CI: 1.03-1.71), and ADA compared to MTX (PsA, HR: 1.69, 95% CI: 1.17-2.44; PsO, HR: 1.32, 95% CI: 1.07-1.64).

Conclusion:

Among psoriatic arthritis and psoriasis patients enrolled in Medicare, adalimumab had higher rates for NMSC relative to comparator treatments.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/risk-of-non-melanoma-skin-cancer-among-medicare-psoriasispsoriasis-arthritis-patients/