The incidence of, risk factors for, and sequelae of herpes zoster among HIV patients in the highly active antiretroviral therapy era

Background: Whereas the incidence, risk factors, and clinical sequelae of herpes zoster have been studied in the general population and in HIV patients in the era before highly active antiretroviral therapy (HAART), they have yet to be fully understood in the current era of HAART. Methods: We conducted a retrospective cohort study of patients enrolled in an urban HIV clinic between January 1, 1997 and December 31, 2001. Patients with an episode of herpes zoster during this period were identified, and their charts were reviewed. A nested case-control analysis was used to assess factors associated with an initial episode of herpes zoster. Multivariate conditional logistic regression analyses were used to assess risk factors for zoster. Logistic regression was performed to assess factors associated with complicated zoster. Results: Two hundred eighty-two episodes of herpes zoster were identified in 239 patients. Of these episodes, 158 were new occurrences of zoster and 124 were recurrent zoster events. The incidence of zoster during the study period was 3.2 per 100 person-years of follow-up. The incident cases reflected the clinic population, with most patients being male (63%) and African American (77%) and having injection drug use as their HIV risk factor (49%). The mean age of the patients was 41 years. Sixty-seven percent of patients had single dermatomal involvement, and the thorax was involved in 41%. In multivariate regression, being on HAART (odds ratio [OR] = 2.39, 95% confidence interval [CI]: 1.65 to 3.49) and a CD4 count of 50 to 200 cells/mm(3) (OR = 2.69, 95% CI: 1.44 to 5.01) compared with a CD4 count less than 50 cells/mm(3) were associated with an increased risk of zoster. Twenty-eight patients (18%) developed post-herpetic neuralgia (PHN), and 29 patients (18%) had other complications. Male-to-male sex as an HIV risk factor (P = 0.02) and being on HAART at a zoster episode (P = 0.03) were protective against complicated zoster. Conclusions: Our results suggest that zoster infection rates have not changed in the current HAART era but that a significant percentage of patients develop complications, particularly PHN, which is quite remarkable considering the young age of our population.