Incidence and predictors of herpes zoster among antiretroviral therapy-naïve patients initiating HIV treatment in Johannesburg, South Africa

Abstract

To describe the characteristics of HIV-infected patients experiencing herpes zoster after antiretroviral therapy (ART) initiation and to describe the incidence and predictors of a herpes zoster diagnosis. Adult patients initiating ART from April 2004 to September 2011 at the Themba Lethu Clinic in Johannesburg, South Africa were included. Patients were followed from ART initiation until the date of first herpes zoster diagnosis, or death, transfer, loss to follow-up, or dataset closure. Herpes zoster is described using incidence rates (IR) and predictors of herpes zoster are presented as subdistribution hazard ratios (sHR) and 95% confidence intervals (95% CI). Fifteen thousand and twenty-five patients were included; 62% were female, the median age was 36.6 years, and the median baseline CD4 count was 98 cells/mm(3). Three hundred and forty patients (2.3%) experienced herpes zoster in a median of 26.1 weeks after ART initiation. Most (71.5%) occurred within 1 year of initiation, for a 1-year IR of 18.1/1000 person-years. In an adjusted model, patients with low CD4 counts (<50 vs. ≥200 cells/mm(3); sHR: 1.71, 95% CI: 1.21-2.47) and with a prior episode of herpes zoster (sHR: 1.53, 95% CI: 0.97-2.28) were at increased risk of incident herpes zoster. While only 2% of patients were diagnosed with herpes zoster in this cohort, patients with low CD4 counts and those with prior episodes of herpes zoster were at higher risk for a herpes zoster diagnosis.