Risk of Herpes zoster in patients with psoriasis treated with biologic drugs

Background: Little is known about the risk of herpes zoster (HZ), among patients with psoriasis treated with biologic drugs.

Objective: To determine the incidence of HZ in patients with psoriasis and the association between HZ and use of biologic drugs in these patients.

Methods: The study was performed utilizing the medical database of Clalit Health Services in Israel. The incidence of HZ events was calculated among patients with psoriasis treated with phototherapy, traditional systemic medications and biologic drugs. Incidence rates of HZ events were calculated for each medication, as well as hazard ratios adjusted for age, sex and healthcare utilization burden.

Results: Among 22,330 psoriasis patients (215,656 person-years), 1321 HZ cases were diagnosed. The crude incidence rates per 1000 person-years were 6.0 for UVB phototherapy (95% confidence interval (CI), 0-12.8), 10.1 for PUVΑ (1.3-19.0), 5.4 for acitretin (2.2-8.7), 17.0 for methotrexate (10.6-23.4), 13.9 for etanercept (0.3-27.4), 19.3 for infliximab (0-45.8) and 4.6 for controls (CI, 4.3-5.0). No cases of HZ were seen among patients treated with alefacept, efalizumab or adalimumab. In a multivariate analysis, age, female sex, healthcare utilization pattern and corticosteroid treatment were associated with the time to HZ infection. The association of HZ with infliximab approached statistical significance (Hazard ratio: 1.77, 95% CI: 0.92-3.43), but none of the other biologic drugs were significantly associated with the risk of HZ.

Conclusion: Among patients with psoriasis, treatment with some biologic drugs was associated with a higher incidence of HZ compared with controls, though the difference was not statistically significant.