GEOGRAPHIC AND RACIAL ASPECTS OF HERPES ZOSTER: THE FAMCICLOVIR DATABASE PROJECT

E.M. Nagasako (1), R.W. Johnson (2), D.R.J. Griffin (3), and *R.H. Dworkin (1)
(1) Department of Anesthesiology, University of Rochester Medical Center, Rochester, New York; (2) Department of Anesthesiology, Bristol Royal Infirmary and University of Bristol, Bristol, United Kingdom; (3) SmithKline Beecham Pharmaceuticals, Harlow, Essex, United Kingdom

Geographic and racial factors have been reported in studies of the epidemiology of varicella and herpes zoster. To further clarify the relationships between geographic and racial factors and the characteristics of the acute herpes zoster infection, data from five separate clinical trials of the antiviral agent famciclovir were examined. All studies were randomized, multicenter, double-blind trials conducted in immunocompetent herpes zoster patients in which treatment with famciclovir was compared with either acyclovir or placebo (total n = 2074). Four studies were conducted in the United Kingdom, Europe, and North America, and one study was conducted in Asia, North Africa, and the Middle East.
The following data, collected within 72 hours of rash onset and before any treatment was begun, were examined: age, sex, racial group (Asian, Black, Caucasian), acute pain severity (none, mild, moderate, severe), rash duration at enrollment (< 24 hours, 24-48 hours, 48-72 hours), and geographic region (temperate, tropical). The relationships between racial group and geographic region and the remaining variables were examined in a series of analyses of variance and chi-square tests in the entire sample and separately in the non-Caucasian subgroup (Asian and Black). Non-Caucasian racial group and tropical region were each significantly associated with younger age at zoster onset, smaller percentage of female patients, longer rash duration at enrollment, and greater acute pain severity. In analyses of the non-Caucasian subgroup alone, the Black and Asian patients did not significantly differ in pain severity, age, or sex; however, the Black and Asian patients from tropical regions had significantly lower age at onset, greater rash duration at enrollment, and higher acute pain severity than those from temperate regions.
Prospective studies have demonstrated that greater age and greater acute pain severity are potent risk factors for postherpetic neuralgia. Multiple regression and logistic regression analyses were conducted to examine the relationships between these two risk factors and the demographic variables. Controlling for sex and rash duration, tropical region and non-Caucasian racial group were found to be independently associated with lower age at zoster onset. Controlling for age, sex, and rash duration, tropical region and non-Caucasian racial group were also found to be independently associated with the
presence of moderate to severe pain. These results support racial group and geographic region as independent factors associated with age at onset and acute pain severity in patients with herpes zoster.

Data collection and analysis were supported by grants from SmithKline Beecham Pharmaceuticals.

Corresponding Author: R.H. Dworkin, Ph.D., Professor of Anesthesiology, Oncology, and Psychiatry, Department of Anesthesiology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 604, Rochester, NY 14642, USA