Time to Recurrence of Shingles (Herpes Zoster) Infection

• Activity Number: 26
• Type: Contributed
• Date/Time: Sunday, August 3, 2008 : 2:00 PM to 3:50 PM
• Sponsor: Section on Statistics in Epidemiology
• Author(s): Peter C. Wollan*+ and Patricia Saddier and Barbara P. Yawn
• Companies: Olmsted Medical Center and Merck & Co., Inc. and Olmsted Medical Center
• Keywords: multiple-event survival analysis ; Cox regression

Abstract

Yawn et al (Mayo Clinic Proceedings, 2007) reported a population-based study of herpes zoster (HZ) incidence for the years 1996-2001, funded by Merck and Co., Inc. As a follow-up study, the medical records of the 1669 HZ index cases were re-examined to identify HZ recurrences. New episodes after the index episode were found in 95 subjects, with 8 subjects having more than one. Overall, the 8-year recurrence rate was 6.6% (Kaplan-Meier estimate). Females and those with impaired immune status had significantly higher risk. Older subjects had a slightly higher recurrence rate, but the difference was not statistically significant. In addition, 93 events were identified prior to the HZ index episode. We discuss alternative approaches to analyzing these observations, including the conditional multiple-event model, basing time on subject's age, and basing time on first event.