Incidence, Risk Factors, and Consequences of Human Alphaherpesvirus Infections in Patients With Psoriasis Who...

Immunosuppressive agents may increase the risk of infections with human alphaherpesviruses.

We included all adult patients with moderate to severe psoriasis who initiated methotrexate (MTX) or biologic agents in a retrospective cohort study. An episode of alphaherpesviruses infection was defined as filling a prescription for systemic acyclovir, valacyclovir, or famciclovir. Using nationwide registries, we determined the incidence, risk factors, 180-day hospital contacts, and 30-day mortality following infection.

We included 7294 patients; 4978 (68%) received MTX, and 2316 (32%) biologic agents. The incidence rates (95% confidence intervals) of alphaherpesviruses were 23 (20-27), 26 (19-35), 17 (11-27), and 6.7 (1.3-21) per 1000 person-years of follow-up in patients on MTX, tumor necrosis factor alpha (TNF-α) inhibitors, interleukin 12/23 (IL-12/23) inhibitors, and interleukin 17 (IL-17) inhibitors, respectively. Males had an unadjusted hazard ratio (HR) of 0.47 (P < .001) for alphaherpesvirus infection. Patients on IL-17 inhibitors had an adjusted HR of 0.24 (P = .048) compared to TNF-α inhibitors. Within 180 days after infection, 13%, 7.5%, and <0.5% of patients on MTX, TNF-α inhibitors, and IL-12/23 or IL-17 inhibitors, respectively, had hospital contacts, and the 30-day mortality for all groups was <0.5%.

The incidence and risk of alphaherpesvirus infections were comparable between patients on MTX and TNF-α inhibitors, whereas use of IL-17 inhibitors was associated with a lower risk.