Incidence and risk factors for herpes zoster in patients undergoing liver transplantation

Herpes zoster (HZ) is the most common manifestation of latent varicella zoster virus reactivation, which occurs naturally as a result of aging or in immunocompromised patients. Solid organ transplant recipients are at increased risk for HZ owing to their chronic immunosuppression. Although several reports investigated risk factors for the development of HZ in heart or renal transplantation, data in liver transplantation (LT) are limited.

We evaluated clinical data retrospectively in 377 adult patients undergoing LT between January 2005 and December 2012 in our institution. We analyzed the incidence rate of HZ and the standardized incidence ratio (SIR) by comparing with the general Japanese population. We additionally investigated risk factors for HZ after LT.

HZ developed in 27 (7.16%) of the 377 patients after LT. The incidence rate of HZ after LT was 17.83 per 1000 person-years, which was significantly higher than in the general Japanese population (SIR = 4.61; 95% confidence interval [CI], 4.13-5.14). Multivariate analysis showed that older age (hazard ratio [HR] = 3.95; P < 0.001) and exposure to mycophenolate mofetil (HR = 3.03; P = 0.007) were independent risk factors for HZ after LT.

This is the first and largest study, to our knowledge, to investigate the incidence rate of HZ and risk factors for development of HZ after LT in the Japanese population. Further investigations to focus on immunosuppressive regimens to reduce the risk for HZ incidence in this high-risk population could establish a new protocol of immunosuppression after LT.